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This thesis describes the calculations and proceedings, as well as the theoretical basis behind them, to properly complete the post-process of a CFD analysis of the flow around the McDonnell- Douglas 30P30N airfoil. This completion includes the computations of the relevant magnitudes and the validation of the mesh used comparing the results with the obtained with a finer one and with the results found in the literature. Magnitudes characterizing the boundary layer such as the boundary layer thickness, displacement thickness, momentum thickness and velocity profiles are computed; Also measurements over the shear layer of the slat cove such as the turbulence kinetic energy, velocity magnitude and spanwise vorticity. All the results show sufficient agreement with both a finer mesh that followed the same analysis, as well as the empirical and computational values seen in earlier literature, validating the results and the mesh used.

This project aims to investigate the aerodynamic performance of a stock car and two modified versions of it through Computational Fluid Dynamics (CFD) simulations and wind tunnel testing. The modifications include the addition of a front lip, a front splitter, flat underbody, diffuser and wing. The objectives of the project are to analyze the aerodynamic behavior of the three models, quantify the effects of each modification, and compare the simulation results with the wind tunnel tests. The hypothesis is that almost all the modifications will increase downforce and reduce drag, resulting in improved stability and higher speeds. Except for the wing, that will highly increase the downforce, but it will also increase the drag. The project's methodology includes the 3D design of the three models, using Computer Aided Design (CAD) software named CATIA V5. CFD simulations and the post-processing of the results to obtain drag and lift coefficients are done using Ansys Student software. Wind tunnel tests are also conducted on scaled models, printing it with a 3D printer, to compare the simulation results with real-world data. Wind tunnel used on the project is the one we have in university, named GUNT Hamburg HM170. Theoretical background covers fundamental governing equations of fluid dynamics, aerodynamic forces and moments, variation of drag and lift with car speed, and the aerodynamic effects of front lips, front splitters, flat underbody, diffusers, and wings. The project's significance lies in its potential to improve the aerodynamic performance of high-speed vehicles, leading to increased safety, stability, and speed. The results could also have implications for the automotive industry in terms of the design and optimization of race cars and high-performance vehicles. In conclusion, this project aims to investigate the aerodynamic behavior of a stock car and two modified versions of it through computational fluid dynamics simulations and wind tunnel testing. The project's objectives are to analyze the aerodynamic effects of each modification and compare the simulation results with wind tunnel tests. The hypothesis is that the modifications will increase downforce and reduce drag, resulting in improved stability and higher speeds. The project's significance lies in its potential to improve the aerodynamic performance of high-speed vehicles and has implications for the automotive industry.

In this work, a novel approach for airborne filtration with particular reference to medical (non-oil) medical mask is discussed. Here, and contrariwise to current approaches, filtration is attained neither by reducing the hydraulic diameter of the pore nor by increasing the fibre layers thickness-both of them with a strong penalty in the breathability of the mask, but rather by aerodynamic focussing and growth of the particles themselves. Aerodynamic focussing of particles is achieved by a proper simple parallel rearrangement of the traditional crisscrossing fibres-a configuration which we called the aerolayer; and the growth by coalescence. Utilizing a simplified geometrical and physical model, an expression for the required length of the aerolayer was derived. It is shown that the aerolayer is not only able to increase the probability of capture for small particles but also can potentially improve the breathability by reduction of the total thickness of the current layers required. Additional R &D is required in order to arrive to the most optimized practical design of the aerolayer

[EN] For the safe operation of a sailplane up to the certified maximum speed, the freedom from flutter must be ensured, i.e. no undamped vibrations can occur. The flutter analysis procedure involves obtaining the modal data by computational or experimental means and coupling it with an aerodynamic model to form an aeroelastic model. The state of the art for modelling the unsteady aerodynamic forces is the use of potential-theoretic unsteady vortex lattice or doublet lattice methods. However, viscous effects, such as the forming boundary layer, cannot be modelled with these methods. In order to represent compressible and viscous effects, higher order computational fluid dynamics (CFD) methods can be applied. The aim of this work is to perform steady-state and transient CFD calculations on a modern laminar wing with trailing edge flaps in order to obtain a more accurate computational prediction of the flap coefficients. For this purpose, the simulation of the transition between a laminar and turbulent boundary layer is extremely important., [ES] Para el funcionamiento seguro de un planeador hasta la velocidad máxima certificada, se debe garantizar la ausencia de flameo, es decir, que no se produzcan vibraciones no amortiguadas. El procedimiento para el análisis del flameo implica obtener los datos modales por medios computacionales o experimentales y acoplarlos con un modelo aerodinámico para formar un modelo aeroelástico. La técnica de última generación para modelar las fuerzas aerodinámicas no-estacionarias consiste en el uso de métodos de red de vórtices. Sin embargo, los efectos viscosos, como la formación de la capa límite, no se pueden modelar con estos métodos. Para representar los efectos compresibles y viscosos, se pueden aplicar métodos de dinámica de fluidos computacional (CFD) de orden superior. El objetivo de este trabajo es realizar cálculos CFD de estado estacionario y transitorio en un ala laminar moderna con flaps de borde de fuga para obtener una predicción computacional más precisa de los coeficientes de flaps. Para este propósito, la simulación de la transición entre una capa límite laminar y turbulenta es extremadamente importante.

El tema de las estructuras neumáticas, en concreto los hangares hinchables, es un pequeño sector en el ámbito de la construcción que está en constante desarrollo y en el que existe un amplio margen de mejora, innovación e investigación que supone un reto en términos de cálculo y diseño. Por este motivo, existen varios estudios que intentan optimizar el análisis de esta tipología, que no cuenta con una norma específica. Entre los enfoques alternativos es posible encontrar estudios que van desde los modelos numéricos basados en normas de construcción hasta la mecánica de fluidos computacional. Sin embargo, en el primer caso no son suficientemente precisos o en el segundo el coste computacional los hace excesivos en el diseño práctico. Por este motivo, y con el fin de optimizar el análisis práctico con precisión y coste computacional razonable CIMNE está desarrollando actualmente el Túnel de Viento Virtual (VWT), una nueva solución que combina la aerodinámica de flujo potencial, la dinámica estructural FE explícita y el acoplamiento FSI escalonado. La tesis pretende realizar un estudio exhaustivo sobre el análisis estructural de hangares hinchables para optimizar su cálculo en base al nuevo código computacional. El estudio experimental se realiza mediante un análisis exhaustivo y la comparación de los resultados obtenidos con VWT y RAMseries, teniendo en cuenta como factor determinante la diferencia de aplicación de las cargas debidas al viento. La comparación se basa en la evaluación de las variables de estudio aerodinámico y estructural en función de condiciones como la dirección del viento, la velocidad del viento y una variación en la geometría de la estructura. Finalmente, se concluye que las capacidades de la herramienta computacional del Túnel de Viento Virtual (VWT) presentan resultados que pueden ser de óptima utilidad en la aplicación industrial al análisis y diseño estructural de estructuras hinchables. The subject of pneumatic structures, specifically inflatable hangars, is a small sector in the field of construction which is in constant development and where there is a wide margin for improvement, innovation, and research which is a challenge in terms of calculation and design. For this reason, there are several studies that attempt to optimize the analysis of this typology, which does not have a specific standard. Among the alternative approaches, it is possible to find studies ranging from numerical models based on building standards to computational fluid mechanics. However, in the first case, they are not sufficiently accurate, or in the latter, the computational cost makes them excessive in the practical design. For this reason, and in order to optimize the practical analysis with accuracy and reasonable computational cost, CIMNE is currently developing Virtual Wind Tunnel (VWT), a new solution combining potential flow aerodynamics, explicit FE structural dynamics, and staggered FSI coupling. The thesis aims to carry out an exhaustive study on the structural analysis of inflatable hangars in order to optimize their calculation based on the new computational code. The experimental study is carried out by means of exhaustive analysis and comparison of the results obtained with VWT and RAMseries, taking into account as a determining factor the difference in the application of the loads due to the wind. The comparison is based on the evaluation of the aerodynamic and structural study variables as a function of conditions such as wind direction, wind velocity, and a variation in the geometry of the structure. Finally, it is concluded that the capabilities of the Virtual Wind Tunnel (VWT) computational tool present results that can be of optimal utility in the industrial application to the analysis and structural design of inflatable structures.

This project is based on a collaboration through the Universitat Politècnica de Catalunya and ONAerospace. This is the preliminary design concept for an e-VTOL (All-electric Vertical Take-Off and Landing) aircraft. Therefore, in order to carry it out, it has been decided to organize it with 4 divisions: aerodynamics, propulsion, flight mechanics and avionics. The first e-VTOL was patented by Nikola Tesla in 1928. Since then, these planes have been varying and developing. Nowadays, they have been approached in a different way than they were previously. Now, several companies are investing in the research of these aircraft, as a new idea of ¿¿aerotaxi is emerging. One of these companies is ONA Aerospace, which is being collaborated with on this project. Therefore, we want to focus on this e-VTOL not only as an air taxi, but also as a rescue aircraft. The main objective of this project is to make the initial study of the flight mechanics of this e-VTOL aircraft. In other words, study its mechanics by establishing the body axes and wind axes of the aircraft and stipulating the different equations of motion. On the other hand, it is also necessary to study the different performances, since one of the most significant characteristics of the e-VTOL, which in fact makes this aircraft called an e-VTOL, is the take-off and vertical landing. In addition, together with the Aerodynamics Department, the study of stability and control has been carried out. From the aerodynamics side, a CFD simulation has been prepared using ANSYS software to obtain several parameters with which, in this project, it has been studied whether they met the conditions to obtain a longitudinal stability behavior. In addition, in this project a CFD simulation has been carried out for the design of the vertical tail in order to study the lateral-directional stability. Finally, the different moment coefficients have been studied to determine the maneuverability of the aircraft. It has been possible to confirm and conclude that the e-VTOL is stable both longitudinally, laterally and directionally and for pulling and turning maneuvers. In addition, in the transition phase there is a loss of lift because the rear engines are tilting, but this tilt will introduce a forward thrust that will allow the wings and canards to start generating lift. Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

Aerodynamic design of a Formula Student racing car using Solidworks Flow Simulation. The devices designed are compatible with the Vilanova Formula Team 2022 racing car. The project also contains the development of a deep learning tool to test the track efficiency of the car. This tool compares different aerodynamic configurations in a determined track before building the car.

[ES] El presente documento se ocupa del estudio de una turbina eólica de nuevo diseño pensada para ingresar en el mercado eólico urbano de poca potencia. El diseño inicial pertenece a la start-up “AirCrafted” que trabaja en el ´ámbito de energía renovables e industria de la aviación. La turbina eólica se caracteriza por ser de eje vertical, y recibe el nombre de “RoDaVi”, acrónimo de Rotor de Da Vinci, porque su diseño se basa en la optimización de las primeras ideas del inventor. En cuanto a resultados, en la tesis se realiza un análisis preliminar con modelos a escala 1:10 de la turbina en una balanza dinamométrica para conocer los parámetros aerodinámicos de la turbina y la influencia de las diferentes configuraciones y diseños en el túnel de viento (velocidad, ´ángulo de ataque, grosor, ...). Más adelante se realiza con una turbina de escala 1:3, un análisis de las prestaciones eléctricas de la turbina para diferentes ´ángulos y velocidades de flujo. El tamaño seleccionado se debe a las limitaciones del túnel de viento. La turbina se encuentra conectada a un generador síncrono de imanes permanentes, que a su vez se conecta a un sistema eléctrico que simularía una carga de batería real. Se realizan diferentes mediciones con varios motores de los parámetros eléctricos principales utilizando sensores como un torsiómetro y un vatímetro. El ´ultimo análisis se realiza con la tecnología PIV. Se utilizan un láser, una foto cámara de alta potencia y generador de micro burbujas para estudiar el campo fluido (velocidades y vorticidad)., [EN] This document deals with the study of a newly designed wind turbine intended for entering the low power urban wind market. The initial design belongs to the start-up “AirCrafted” that works in the field of renewable energy and the aviation industry. The wind turbine is characterized by a vertical axis, and is called “RoDaVi”, an acronym for Da Vinci rotor, because its design is based on the optimization of the inventor’s early ideas. Regarding results, in the thesis a preliminary analysis is carried out with 1:10 scale models of the turbine in a dynamometric balance to know the aerodynamic parameters of the turbine and the influence of the different configurations and designs in the wind tunnel ( speed, angle of attack, thickness, ...). Later, with a 1:3 scale turbine, an analysis of the electrical performance of the turbine for different angles and flow speeds is carried out. The size selected is due to the limitations of the wind tunnel. The turbine is connected to a permanent magnet synchronous generator, which in turn is connected to an electrical system that would simulate a real battery charge. Different measurements are made with various motors of the main electrical parameters using sensors such as a torque meter and a wattmeter. The last analysis is performed with PIV technology. A laser, a high power photo camera and a micro bubble generator are used to study the fluid field (velocities and vorticity)., [CA] Aquest document s’ocupa de l’estudi d’una turbina eòlica de nou disseny pensada per ingressar al mercat eòlic urbà de poca potència. El disseny inicial pertany a la start-up AirCrafted que treballa en l’àmbit d’energia renovables i indústria de l’aviació. La turbina eòlica es caracteritza per ser d’eix vertical, i rep el nom de RoDaVi, acrònim de rotor de Da Vinci, perquè el seu disseny es basa en l’optimització de les primeres idees de l’inventor. Quant a resultats, a la tesi es realitza una anàlisi preliminar amb models a escala 1:10 de la turbina en una balança dinamometrica per conèixer els paràmetres aerodinàmics de la turbina i la influència de les diferents configuracions i dissenys al túnel de vent ( velocitat, angle d’atac, gruix,...). Més endavant es fa amb una turbina d’escala 1:3, una anàlisi de les prestacions elèctriques de la turbina per a diferents angles i velocitats de flux. El tamany seleccionat es deu a les limitacions del túnel de vent. La turbina es troba connectada a un generador síncron d’imants permanents, que a més es connecta a un sistema elèctric que simularia una càrrega de bateria real. Es realitzen diferents mesuraments amb diversos motors dels paràmetres elèctrics principals utilitzant sensors com un torsiòmetre i un vatímetre. L’última anàlisi es realitza amb la tecnologia PIV. Es fan servir un làser, una foto càmera d’alta potència i un generador de micro bombolles per estudiar el camp fluid (velocitats i vorticitat)

Aerodynamic performances may be optimised by the appropriate tuning of Active Flow Control (AFC) parameters. For the first time, we couple Genetic Algorithms (GA) with an unsteady Reynolds-Averaged Navier-Stokes (RANS) solver using the Spalart-Allmaras (SA) turbulence model to maximise lift and aerodynamic efficiency of an airfoil in stall conditions [1], and then validate the resulting set of optimal Synthetic Jet Actuator (SJA) parameters against well-resolved three-dimensional Large Eddy Simulation (LES). The airfoil considered is the SD7003, at the Reynolds number and the post-stall angle of attack . We find that, although SA-RANS is not quite as accurate as LES, it can still predict macroscopic aggregates such as lift and drag coefficients, provided the free-stream turbulence is prescribed to reasonable values. The sensitivity to free-stream turbulence is found to be particularly critical for SJA cases. Baseline LES simulation agrees well with literature results, while RANS-SA would seem to remain a valid model to a certain degree. For optimally actuated cases, our LES simulation predicts far better performances than obtained by suboptimal SJA LES computations as reported by other authors [2] for the same airfoil, Re and a, which illustrates the applicability and effectiveness of the SJA optimisation technique applied, despite using the less accurate yet computationally faster SA-RANS. The flow topology and wake dynamics of baseline and SJA cases are thoroughly compared to elucidate the mechanism whereby aerodynamic performances are enhanced This work was supported by the Spanish Government under grants FIS2016-77849-R and PID2020-114043GB-I00 and by the Catalan Government under grant 2017-SGR-00785. Computations were performed in the Red Española de Supercomputación (RES), Spanish supercomputer network, under the grants IM-2019-3-0002 and IM-2020-1-0001. F. M. is a Serra-Húnter fellow

The world is going through a constant evolution, where the objectives are much more ambitious than before thanks to the new technologies. However, the focus is no longer on only improving existing services without considering anything else; nowadays, the benefit provided is just as important as the way in which it is achieved, and the main efforts currently are focused on achieving a sustainable world, in which life continues to be as we know it and climatic catastrophes are eradicated, at least those in which human activity is the main cause. That is why this thesis is focused on the implementation in the aeronautical industry of a promising technology called Active Flow Control (AFC). To that end, an exhaustive state-of-the-art is conducted in which the AFC technology is described in general, to then deep dive in its aeronautical applications. Next, the technology required so as to implement the AFC in an aircraft is described, covering the main elements needed to influence the flow around the aircraft together with the power supply architectures necessary to feed the actuators. On the other hand, and based on the information previously gathered, a Minimum Viable Product (MVP) is defined, in which AFC technology is to be implemented in an Airbus A-320 aircraft. In the MVP, both the technological elements that need to be installed together with the system infrastructure are established, thus defining the architecture of the product. In order to ensure the viability and profitability of the MVP, a feasibility study is conducted, analysing the installation of the product from an airline perspective considering three different casuistic: an aircraft that flies only at national level in Spain, an aircraft that flies at international level in Europe and a complete fleet of Airbus A-320 that flies at international level in Europe. The preliminary economic analysis covers the three cases mentioned, and the complete economic figures are presented for the third case, the one with more practical interest. On the other hand, the regulatory emissions framework currently in place in Europe is described, assessing whether the installation of the MVP in a European airline could influence the overall company strategy towards the 2050 zero net goal achievement. Due to the current situation, in which the global awareness of contaminant gases emissions has increased considerably, all the projects aiming to reduce this type of emissions have a great impact in the industry, and the AFC technology investigations are a good opportunity to improve aeronautical industry contaminant footprint in the world.

This thesis provides an study of the flow around a McDonnell Douglas 30P30N with an Active Flow Control device, a synthetic jet, with different configurations. The flow is two dimensional, with a Reynolds number of 1.7·10⁶ , an Angle of Attack of 5.5⁰ and a Mach of 0.7. The purpose of this device is to reduce the drag and increases the lift by reducing the vortex shedding at the wake by retarding the boundary layer detachment. Several Reynold Averaged Navier-Stokes simulations have been performed to determine the configuration where the maximum aerodynamic efficiency is reach. It has been concluded that the actuation is highly dependant on the position of the actuator; placed after the suction region has been two time more efficient than placed on it. In addition to this, it has been observed that the efficiency increased with the momentum coefficient, the nondimensional frequency and the angle of the exhaust velocity. All of them have played a major role on the actuation.

The practical evaluation of aerodynamic coefficients in unconventional concrete structures requires specific studies, which are small-scale models evaluated in wind tunnels. Sophisticated facilities and special sensors are needed, and the tendency is for modern and slender constructions to arise with specific demands on their interaction with the wind. On the other hand, the advances obtained in modern multi-core processors emerge as an alternative for the construction of sophisticated computational models, where the Navier-Stokes differential equations are solved for fluid flow using numerical methods. Computations of this kind require specialized theoretical knowledge, efficient computer programs, and high-performance computers for large-scale calculations. This paper presents recent results involving two real-world applications in concrete structures, where the aerodynamic parameters were estimated with the aid of computational fluid dynamics. Conventional quad-core computers were applied in simulations with the Finite Volume Method and a progressive methodology is presented, highlighting the main aspects of the simulation and allowing its generalization to other types of problems. The results confirm that the proposed methodology is promising in terms of computational cost, drag coefficient estimation and versatility of simulation parameters. These results also indicate that mid-performance computers can be applied for preliminary studies of aerodynamic parameters in design offices. Resumo A avaliação prática dos coeficientes aerodinâmicos em estruturas de concreto não convencionais demanda estudos específicos, que consistem em modelos em escala reduzida, em túnel de vento, para estimativa desses parâmetros. Instalações sofisticadas e sensores especiais são necessários, e a tendência é que as construções modernas, cada vez mais esbeltas e arrojadas, surjam com demandas específicas em relação a sua interação com o vento. Por outro lado, o avanço obtido em processadores modernos do tipo multi-núcleo, emerge como uma alternativa para a construção de modelos computacionais sofisticados, onde as equações diferenciais de Navier-Stokes são resolvidas para o escoamento do fluido por meio de métodos numéricos. Análises deste tipo demandam conhecimento teórico especializado, programas computacionais eficientes e computadores de alta performance para cálculos em larga escala. Este artigo apresenta resultados recentes envolvendo duas aplicações reais em estruturas de concreto, onde os parâmetros aerodinâmicos foram estimados com o auxílio da dinâmica dos fluidos computacional. Computadores convencionais do tipo quad-core foram empregados em simulações com o Método dos Volumes Finitos e uma metodologia progressiva é apresentada, destacando os principais aspectos da simulação e permitindo a sua generalização a outros tipos de problemas. Os resultados confirmam que a metodologia proposta é promissora em termos de custo computacional, estimativa do coeficiente de arrasto e versatilidade dos parâmetros da simulação. Esses resultados confirmam que computadores de média performance podem ser aplicados a estudos preliminares de parâmetros aerodinâmicos em escritórios de projeto.

The following study refers to the analysis of the performance and improvements of the most famous motorsport competition in the world, known as Formula One. Within this sport, numerous sections such as mechanics, chassis or engines are included, but in this case, we will introduce ourselves in the investigation of the front wing, one of the most important elements of aerodynamics. Like all sports do, Formula One has also evolved, and in this case, we will focus our project on the creation of a new front wing design adapted to new regulations imposed by the FIA in 2022. So, our main objectives are creating this new 3D CAD model in SolidWorks, thanks to other prototypes and images, and also starting a discussion process where the improvements provided by this new design are compared to previous years. The methodology starts with the creation of the 2022 prototype and reproduce it in a CFD simulation software studying the dynamic behaviour of the air like a virtual wind tunnel. The project explains in detail the operation of these simulations, and the methodology used in their creation, based on images, tables and conclusions obtained in the course of the work. Once seen the most important aerodynamic aspects, located in the initial part of the memory, and the evolution of aerodynamics in the sport throughout history, some comparisons are made with a 3D model obtained from a 2018 front wing (old regulation) thanks to the CFD simulations already commented. Simulations generate numerous data and results that must be considered and commented to find the differences between these two ailerons, where a symbolic value is the numeric aerodynamic efficiency that includes information about lift and drag coefficients, which can arrive to increase considerably with the new model. Also, with the results, we arrive at the conclusion that a car’s configuration is crucial to find the best performance, and small changes, like the height or geometry of the front wing, can be decisive. To sum up, our final conclusions will generalize and compare which is the best front wing configuration and if the FIA’s objective to reduce the amount of dirty air with a new regulation can be accomplished. Besides, some other future ideas to enhance our study, like different changing performance effects or advanced considerations, are remarked.

És ben conegut l’impacte que té sobre el rendiment aerodinàmic, el fet d’incorporar un sòl pla i un difusor a un vehicle. Normalment els difusors se solen centrar en l’eix de simetria longitudinal. No obstant, la transferència de massa en trajectòries corbes a causa de la inèrcia, desequilibren les forces normals a les rodes interiors i exteriors. L’objectiu d’aquest projecte és el disseny d’un difusor dinàmic, que actuï realitzant un desplaçament transversal com a resposta de l’acceleració lateral. Aquesta implementació ajudaria a reequilibrar les forces normals entre les rodes interiors i exteriors de l'eix posterior. Es bien conocido el impacto que tiene sobre el rendimiento aerodinámico, el hecho de incorporar un suelo plano y un difusor en un vehículo. Normalmente los difusores suelen centrarse en el eje de simetría longitudinal. Sin embargo, la transferencia de masa en trayectorias curvas a causa de la inercia, desequilibran las fuerzas normales en las ruedas interiores y exteriores. El objetivo de este proyecto es el diseño de un difusor dinámico, que actúe realizando un desplazamiento transversal como respuesta a la aceleración lateral. Esta implementación ayudaría a reequilibrar las fuerzas normales entre las ruedas interiores y exteriores del eje trasero. The impact on aerodynamic performance of incorporating plain floor and diffuser in a vehicle is well known. Normally diffusers are usually centered on the longitudinal symmetry axis of the vehicle. However, mass transfers in curved trajectories due to the effect of inertia, unbalance the normal forces on the inner and outer wheels. The objective of this project is the design of a dynamic diffuser, which is actuated by lateral displacement in response to side acceleration. This implementation would help to rebalance the normal forces between the inner and outer wheels of the rear axle.

We optimise a set of Synthetic Jet (SJ) Active Flow Control (AFC) parameters on a SD7003 airfoil in order to maximise lift and aerodynamic efficiency. 2D-RANS with the Spallart Almaras (SA) turbulence model is employed in the optimisation process. The optimal set of SJ parameters is then tested using LES. Comparison between 2D RANS-SA and 3D LES results shows the necessity of tuning the SA model parameters to further improve the reliability of a 2D-simulation-based optimisation. Notwithstanding this, both RANS-SA and LES results show that airfoil efficiency can be drastically improved with SJ AFC

[EN] Stability is one of the most crucial criteria to consider when designing a rocket. It is easily guessable the importance of rockets to reach high speeds during launch. However, the fact of keeping its orientation and its intended flight plan avoiding wobbling and tumbling does not lag behind. Fins are allocated on the tail of the rocket to ensure stability. They try to guarantee that the centre of pressure is always behind the centre of gravity. In such a way, the generated aerodynamic forces act as restoring forces in response to any undesirable rotation that the rocket can suffer. However, they are designed to work stably within a certain range of speeds. Beyond this range, fins can start to fiercely vibrate because of the coupling of two modes of vibration in the aeroelastic system. That is what is known as flutter. It would result in permanent deformations and retaking the control would be practically impossible, leading to catastrophic structural failures. For that reason, rockets fins flutter control must be a priority when dealing with stability. Thus, the aeroelasticity field, concretely the dynamic one, is seriously and deeply studied. During this project, a MATLAB code which predicts rockets fins flutter is completely developed, in order to be able to avoid and control it as much as possible. Furthermore, a flutter simulator is also designed and programmed through the toolbox of Simulink to obtain the answer of those rockets fins in real time. In such a way, through the introduction of certain inputs, the fins behaviour is directly simulated. Finally, some CFD simulations are run so that the flow around those fins can be analysed in more detail and the results obtained with the code are checked., [ES] La importancia de alcanzar altas velocidades durante el lanzamiento de un cohete es muy notoria y evidente. Sin embargo, el hecho de mantener su orientación y su plan de vuelo previsto evitando cualquier tipo de tambaleo no puede quedar atrás. Esto es lo que se conoce como estabilidad, y en caso de no conseguirse, el cohete no sería capaz de completar con éxito su misión. Las aletas se colocan en la cola del cohete para asegurar su estabilidad. Intentan garantizar que el centro de presión quede siempre detrás del centro de gravedad. De esta forma, las fuerzas aerodinámicas generadas actúan como fuerzas restauradoras en respuesta a cualquier giro o perturbación indeseable que pueda sufrir el cohete. No obstante, están diseñadas para funcionar de manera estable dentro de un rango determinado de velocidades. Más allá de este rango, las aletas pueden empezar a vibrar fuertemente debido al posible acoplamiento de dos modos de vibración del sistema aeroelástico, lo que se conoce como aleteo o flameo. Esto provocaría deformaciones permanentes y sería prácticamente imposible retomar el control, ocasionando así fallos estructurales catastróficos e irreversibles. Por esa razón, el control del flameo de las aletas debe ser una prioridad cuando se trabaja en la estabilidad de los cohetes que las usan. Así, el campo de la aeroelasticidad, concretamente el de la aeroelasticidad dinámica, se convierte en el objeto de estudio principal del problema. Durante este proyecto, se desarrolla un código completo que predice el flameo de las aletas de los cohetes a través del software de MATLAB, para así poder evitarlo y controlarlo lo máximo posible. Además, con la finalidad de obtener la respuesta de las aletas de dichos cohetes en tiempo real, también se diseña y programa un simulador del flameo a través de la toolbox de Simulink. De esta forma, mediante la introducción de determinados inputs o parámetros de entrada, el comportamiento de las aletas se simula directamente. Finalmente, se lanzan unas simulaciones CFD con el software de Ansys, Fluent, para analizar con más detalle el flujo alrededor de las aletas, comprobar que los resultados son similares a los obtenidos con el código y, de cierta manera, verificarlo.

[ES] Utilizando la tecnología cada vez más popular y en constante crecimiento de las pilas de combustible basadas en hidrógeno, dadas sus ventajas ambientales sobre los combustibles fósiles. Más concretamente, partiendo de un diseño previamente calculado y basado en estadísticas de un helicóptero ligero de uso civil con capacidad para dos pasajeros, el nuevo sistema de potencia ha sido dimensionado y optimizado iterativamente para diferentes aplicaciones: desde urbanas hasta interurbanas. desplazamientos urbanos a operaciones no tripuladas. Esta metodología iterativa se llevó a cabo con base en los antecedentes teóricos para el diseño aerodinámico de helicópteros, obteniendo aproximaciones de potencia de crucero y de ascenso/descenso, así como el combustible requerido para completar la misión teniendo en cuenta el estado del arte actual de la tecnología involucrada. En el desarrollo de la versión readaptada, el enfoque se centró en el nuevo sistema de potencia, incluyendo cuidadosas consideraciones sobre el rendimiento de sus componentes mediante el uso de simulaciones dinámicas del sistema de pila de combustible a diferentes altitudes basadas en la optimización del sistema de tratamiento del aire y potencia de elementos auxiliares, así como la optimización aerodinámica del sistema de almacenamiento de combustible. Además, se desarrollaron consideraciones basadas en el trabajo de autores anteriores sobre aerodinámica, materiales y distribución del espacio con el fin de maximizar el potencial y dejar espacio para los siguientes pasos en términos de mejora a través de estudios más específicos. Finalmente, se realizó una evaluación del ciclo de vida (L.C.A.), estudiando el impacto ambiental del diseño en comparación con su predecesor y aprovechando la oportunidad para discutir el estado actual de la producción de hidrógeno, así como los desafíos futuros relacionados con esta tecnología., [EN] Using the increasingly popular and evergrowing technology of hydrogen based fuel cells, given their environmental advantages over fossil fuels, and starting from a previously calculated, statistically-based design of a light helicopter for civil use, the aircraft has been recalculated including the new power system, iteratively dimensioned and optimized for different applications: from urban and inter-urban commutes to unmanned operations. This iterative methodology was carried out obtaining approximations of cruise and ascending/descending power, as well as the fuel required to complete the mission accounting for the current state of the art of the involved technology. In the development of the adapted version, focus was centered on the new power system, including careful considerations about the performance of its components by using dynamic simulations of the fuel cell system based on air usage optimization as well as considering the aerodynamic effect of exterior hydrogen tanks. Additionally, future design considerations were suggested based on the work of previous authors involving aerodynamics, materials and space distribution in order to both maximize the potential and leave room for the next steps in terms of improvement through more specific studies. To conclude, a life-cycle assessment (L.C.A.) was performed, studying the environmental impact of the designs compared to their predecessor and use the opportunity to discuss the current state of hydrogen production, as well as future challenges related with this technology.

Aerodynamics in Formula 1 has played a vital role in race car performance over the last decades. 2022 Formula 1 vehicles have faced a significant change in technical regulations due to the return of the ground effect as the main generator of downforce. This dissertation aims to analyse the aerodynamic behaviour of a 2022 Formula 1 front wing using computational fluid dynamics (CFD) compared to a 2021 front wing to comprehend its differences in flow behaviour, as well as carry out the designs of the 2021 and 2022 front wing models following the FIA technical regulations. This study gives a brief explanation of the history of aerodynamics in Formula 1 focused on the evolution of front wings and the influence of downforce in vehicle dynamics. Moreover, it introduces the most influential aerodynamic working principles. Then, a discussion of wings is presented including a comparative analysis of the differences between the 2021 and 2022 front wings. Four simulations have been carried out starting with only the front wings and then including the tyres in motion and the wheel cover for the 2022 model. The outcomes obtained have been analysed to discuss the 2022 front wing performance and vorticity using the downforce and drag coefficient plots, and pressure and velocity distributions. Furthermore, a qualitative analysis of the meshing and a study of the convergence of the simulations has been carried out. La aerodinámica en la Formula 1 ha jugado un rol vital en el rendimiento de los vehículos de competición en las últimas décadas. Los Formula 1 de 2022 se han enfrentado a un cambio significativo de las regulaciones técnicas con el retorno del efecto suelo como principal generador de sustentación negativa. El objetivo de esta tesis es analizar el comportamiento aerodinámico de un alerón delantero de Fórmula 1 de 2022 mediante el uso de la mecánica de fluidos computacional (CFD) en comparación con el alerón delantero de 2021, con el fin de comprender las diferencias de flujo entre estos. Al mismo tiempo, se llevará a cabo el diseño de los alerones delanteros de 2021 y 2022 siguiendo la normativa técnica impuesta por la FIA. Este estudio presenta una explicación breve sobre la historia de la aerodinámica en la Formula 1, especialmente centrado en la evolución del alerón delantero y la influencia de las fuerzas de sustentación negativas en la dinámica del vehículo. A continuación, se introduce los principios aerodinámicos necesarios para la comprensión del proyecto, seguido de la discusión sobre las alas incluyendo un análisis comparativo de las diferencias entre el alerón delantero de 2021 y de 2022. Se han realizado cuatro simulaciones empezando con los alerones delanteros y después incluyendo las ruedas en movimiento y el cubre ruedas para el modelo de 2022. Los resultados obtenidos se han analizado para extraer conclusiones acerca del rendimiento del alerón delantero de 2022 y su vorticidad utilizando los gráficos de los coeficientes de resistencia del aire y de sustentación negativa, y los campos de presión y de velocidad. Además, se ha realizado un análisis cualitativo del mallado y un estudio de la convergencia de las simulaciones. L'aerodinàmica en la Formula 1 ha jugat un rol vital en el rendiment dels vehicles de competició en les últimes dècades. Els vehicles de Formula 1 de 2022 s'han enfrontat a un canvi significatiu de les regulacions tècniques amb el retorn de l'efecte terra com a principal generador de sustentació negativa. L'objectiu d'aquesta tesi és analitzar el comportament aerodinàmic d'un aleró davanter de Fórmula 1 de 2022 mitjançant l'ús de la mecànica de fluids computacional (CFD) en comparació amb l'aleró davanter de 2021, amb la finalitat de comprendre les diferències de flux entre aquests. Al mateix temps, es durà a terme el disseny dels alerons davanters de 2021 i 2022 seguint la normativa tècnica imposada per la FIA. Aquest estudi presenta una explicació breu sobre la història de l'aerodinàmica en la Formula 1, especialment centrat en l'evolució de l'aleró davanter i la influència de les forces de sustentació negatives en la dinàmica del vehicle. A continuació, s'introdueix els principis aerodinàmics necessaris per a la comprensió del projecte, seguit de la discussió sobre les ales incloent una anàlisi comparatiu de les diferències entre l'aleró davanter de 2021 i de 2022. S'han realitzat quatre simulacions començant amb els alerons davanters i després incloent les rodes en moviment i el cobre rodes per al model de 2022. Els resultats obtinguts s'han analitzat per a extreure conclusions sobre el rendiment de l'aleró davanter de 2022 i la seva vorticitat utilitzant els gràfics dels coeficients de resistència de l'aire i de sustentació negativa, i els camps de pressió i de velocitat. A més, s'ha realitzat un anàlisi qualitatiu del mallat i un estudi de la convergència de les simulacions.

[ES] El objetivo de este trabajo es crear un marco numérico para estudiar, por medio de simulaciones URANS, la dinámica de un vehículo aéreo no tripulado sometido a ráfagas de viento y aplicar leyes de control para estabilizar su respuesta. La aeronave se representa por medio de un perfil aerodinámico 2D asociado a un modelo estructural que lo hace naturalmente estable. El software utilizado es StarCCM+ y su módulo de interacción fluido-estructura, DFBI. Se simulan tanto ráfagas frontales como transversales y se implementara un controlador proporcional de cabeceo. Se compara la respuesta del perfil con estudios experimentales existentes., [EN] The aim of this work is to create a numerical framework to study, by means of URANS simulations, the dynamics of an unmanned aerial vehicle subjected to wind gusts and to apply control laws to stabilise its response. The aircraft is represented by means of a 2D airfoil associated with a structural model that makes it naturally stable. The software used is StarCCM+ and its fluid-structure interaction module, DFBI. Both frontal and transverse gusts are simulated and a proportional pitch controller is implemented. The profile response is compared with existing experimental studies.

This article presents the investigation of different grey-area mitigation (GAM) techniques towards achieving accurate subsonic turbulent round jet aerodynamics and aeroacoustics results. Combinations of new adapting subgrid length scales with 2D detecting LES models are used as the GAM technique. The numerical simulations are carried out on a set of refining meshes using two different scale-resolving codes: NOISEtte and OpenFOAM. The results show that all the considered techniques provide appropriate accuracy to predict the noise generated and the importance of both the numerical scheme and how subgrid eddy viscosity is modelled. The work of J.R.P. and F.X.T. has been financially supported by the project RETOtwin (PDC2021-120970-I00) funded by MCIN/AEI/10.13039/501100011033 and European Union Next Generation EU/PRTR. J.R.P. is supported by a FI-DGR 2015 predoctoral contract financed by Generalitat de Catalunya, Spain.

[ES] El trabajo se centra en el estudio del comportamiento del flujo alrededor las alas rígidas de un ornitóptero durante su aleteo. Para ello, se realizan varias medidas de sustentación y arrastre en el túnel de viento mediante una balanza dinamométrica. Se lleva a cabo un análisis paramétrico teniendo en cuenta variables cambiantes como la frecuencia de aleteo, la velocidad del túnel de viento, el ángulo de incidencia y la propia geometría del ala en términos de su relación de aspecto. Una vez encontrados los casos de mayor interés, se analizan mediante la técnica PIV (Particle Image Velocimetry), buscando así una mejor comprensión del comportamiento del flujo de la estela aguas abajo del ornitóptero tanto en el tiempo como en el espacio., [CA] Al llarg de la hist`oria, la capacitat de volar ha despertat un gran inter´es en l’´esser hum`a; qui va prendre de refer`encia als ocells o els insectes amb la finalitat de reproduir el moviment de les seues ales per a aconseguir aquesta fita. No obstant aix`o, segles despr´es dels primers intents es va arribar a una soluci´o diferent a l’esperada, perqu`e es van haver de substituir les ales batents per unes ales fixes perqu`e la seua aerodin`amica resultava m´es f`acil de comprendre. No obstant aix`o, l’aerodin`amica de les ales batents continua resultant molt atractiva a causa del seu potencial, especialment en aplicacions de menor escala com s´on els vehicles aeris no tripulats o, en particular, els micro vehicles aeris, l’estructura dels quals est`a fonamentalment basada en l’anatomia dels insectes. Amb la finalitat d’aprofundir en aquest tema, el seg¨uent document se centra en el comportament del flux al voltant de les ales d’un ornit`opter. Per a aix`o, es construeix el corresponent model junt a tres parells d’ales, totes elles r´ıgides, rectangulars i amb mateixa `area la difer`encia de la qual ´es l’allargament (“Aspect ratio”). S’introdueix el model en el t´unel de vent i mitjan¸cant l’´us d’una balan¸ca dinamom`etrica, es comparen quantitativament les forces aerodin`amiques (“lift” i “drag”) que s’obtenen a diferents velocitats, freq¨u`encies de batuda i angles d’incid`encia. Despr´es d’aix`o, es descarten els casos de menor inter´es i es mesuren de nou els casos `optims mitjan¸cant la t`ecnica PIV (“Particle Image Velocimetry”), podent aix´ı analitzar amb major profunditat com es comporta el flux del deixant aig¨ues avall de l’ornit`opter tant en el temps com en l’espai., [EN] Throughout history, the ability to fly has aroused great interest in humans, who used birds or insects as a reference to reproduce the movement of their wings to achieve this milestone. However, centuries after the first attempts, a different solution than expected was reached, as the flapping wings had to be replaced by fixed wings whose aerodynamics were easier to understand. Nevertheless, the aerodynamics of flapping wings are still very attractive due to its potential, especially in smaller scale applications such as unmanned aerial vehicles or, in particular, micro aerial vehicles, whose structure is fundamentally based on the anatomy of insects. In order to go deeper into this topic, the following document focuses on the flow behavior around the wings of an ornithopter. For this purpose, the corresponding model of the ornithopter is built together with three pairs of wings, all of them rigid, rectangular and with the same area whose difference is the aspect ratio. The model is introduced into the wind tunnel and, using a dynamometric balance, the aerodynamic forces (lift and drag) are obtained at different speeds, flapping frequencies, and angles of incidence. After that, the cases of less interest are discarded and the optimal ones are measured again using the PIV (Particle Image Velocimetry) technique, thus being able to analyze in greater depth how the wake flow behaves downstream of the ornithopter both in time and space.

In this review, we summarize existing trends of flow control used to improve the aerodynamic efficiency of wings. We first discuss active methods to control turbulence, starting with flat-plate geometries and building towards the more complicated flow around wings. Then, we discuss active approaches to control separation, a crucial aspect towards achieving a high aerodynamic efficiency. Furthermore, we highlight methods relying on turbulence simulation, and discuss various levels of modeling. Finally, we thoroughly revise data-driven methods and their application to flow control, and focus on deep reinforcement learning (DRL). We conclude that this methodology has the potential to discover novel control strategies in complex turbulent flows of aerodynamic relevance. R.V. acknowledges the financial support from the Swedish Research Council (VR). O.L. is partially financed by a Ramón y Cajal postdoctoral contract by the Ministerio de Economía y Competitividad, Secretaría de Estado de Investigación, Desarrollo e Innovación, Spain (RYC2018-025949-I).

[EN] In the course of this thesis numerical simulations are carried out for a transonic reference wing as part of the LuFo VI-1 CATeW (Coupled Aerodynamic Technologies for Aircraft Wings) project. The main focus of this work lies on the characterization of the reference wing for a given flight-envelope. Different parameter combinations are evaluated through variations of Reynolds number Re, Mach number Ma and lift coefficient CL, as well as performing various Adaptive Dropped-Hinge Flap (ADHF) deflections to study the effects of implementing Variable Camber (VC) technology. This way, the necessary database is created to evaluate in the future the potential of an application of Hybrid Laminar Flow Control methods combined with a VC wing for net drag reduction at different flight conditions. To ensure the validity of the results obtained, a grid study is performed with a hybrid unstructured grid for a representative flight condition (Ma = 0.83, Re = 34·106, ¿ = 1°, CL = 0.43). For the wing characterization, the analysis is divided into two parts. The first one focuses on the generation of the wing polar curves using the same flight condition as for the grid independence study. The second one aims to cover the complete flight-envelope by creating a space-filling sampling plan, with 15 points distributed over a three-dimensional space considering altitudes from 30000 ft to 40000 ft, Ma values from 0.75 to 0.9, and CL values from 0.3 to 0.6. All numerical simulations are performed with the hybrid Reynolds averaged Navier-Stokes solver DLR TAU-Code, using the Menter-SST k-¿ turbulence model for the baseline studies and the ¿-Re¿ transition model when analyzing the effects of boundary layer transition. Furthermore, different discretization schemes are used comparing the results for both the fully turbulent simulations and the ones considering transition. For the discretization scheme comparison, similar results are obtained for the global aerodynamic behavior of the reference wing when considering conditions inside the linear lift curve range, with increasing differences as more non-linear states are evaluated. As for the boundary layer transition onset prediction, seemingly acceptable results are obtained for the central scheme, with the upwind scheme failing to do so. VC technology is implemented by deformation of the baseline grid, evaluating ADHF deflections of 2° and 4° for the wing polar curve as well as for the sampling points of the flight-envelope, considering boundary layer transition in all of the cases. Whereas it proves to be effective in terms of aerodynamic efficiency increase, it fails to influence significantly the boundary layer transition position., [ES] A lo largo de este trabajo se llevan a cabo simulaciones numéricas de un ala de referencia transónica como parte del proyecto LuFo VI-1 CATeW (Coupled Aerodynamic Technologies for Aircraft Wings). El enfoque principal de este trabajo radica en la caracterización del ala de referencia para una envolvente de vuelo dada. Se evalúan diferentes combinaciones de parámetros a través de variaciones del número de Reynolds Re, el número de Mach Ma y el coeficiente de sustentación CL, además de realizar varias deflexiones de Adaptive Dropped-Hinge Flap (ADHF) para estudiar los efectos de implementar la tecnología de curvatura variable (VC). De esta manera, se crea la base de datos necesaria para evaluar en el futuro el potencial de una aplicación de métodos híbridos de control de flujo laminar combinado con un ala VC para la reducción de la resistencia neta en diferentes condiciones de vuelo. Para asegurar la validez de los resultados obtenidos, se realiza un estudio de independencia de malla con una malla híbrida no estructurada para una condición de vuelo representativa (Ma = 0,83, Re = 34·10^6, ¿ = 1°, CL = 0,43). Para la caracterización del ala, el análisis se divide en dos partes. La primera se centra en la generación de las curvas polares de las alas utilizando las mismas condiciones de vuelo que para el estudio de independencia de malla. La segunda tiene como objetivo cubrir la envolvente de vuelo completa mediante la creación de un plan de muestreo de llenado de espacio, con 15 puntos distribuidos en un espacio tridimensional considerando altitudes de 30000 pies a 40000 pies, valores de Ma de 0,75 a 0,9 y valores de CL de 0,3 a 0,6. Todas las simulaciones numéricas se realizan con el código híbrido de DLR TAU usando las ecuaciones de Navier-Stokes promediadas mediante la descomposición de Reynolds, utilizando el modelo de turbulencia Menter-SST k-¿ para los estudios de referencia y el modelo de transición ¿-Re¿ al analizar los efectos de la transición de la capa límite. Además, se utilizan diferentes esquemas de discretización comparando los resultados tanto para las simulaciones completamente turbulentas como para las que consideran transición. Para la comparación de los esquemas de discretización, se obtienen resultados similares para el comportamiento aerodinámico global del ala de referencia al considerar las condiciones dentro del rango lineal de la curva de sustentación, con diferencias crecientes a medida que se evalúan estados no lineales. En cuanto a la predicción del inicio de la transición de la capa límite, se obtienen resultados aparentemente aceptables para el esquema central, mientras que el esquema upwind no parece proporcionar resultados consistentes. La tecnología VC se implementa por deformación de la malla utilizada como base, evaluando deflexiones ADHF de 2° y 4° para la curva polar del ala así como para los puntos de muestreo de la envolvente de vuelo, considerando transición de la capa límite en todos los casos. Si bien demuestra ser eficaz en términos de aumento de la eficiencia aerodinámica, no influye significativamente en la posición de transición de la capa límite.

A 2D aerodynamic study of the NASA&rsquo, s X-43A hypersonic aircraft is developed using two different approaches. The first one is analytical and based on the resolution of the oblique shock wave and Prandtl&ndash, Meyer expansion wave theories supported by an in-house program and considering a simplified aircraft&rsquo, s design. The second approach involves the use of a Computational Fluid Dynamics (CFD) package, OpenFOAM and the real shape of the aircraft. The aerodynamic characteristics defined as the lift and drag coefficients, the aerodynamic efficiency and the pitching moment coefficient are calculated for different angles of attack. Evaluations are made for an incident Mach number of 7 and an altitude of 30 km. For both methodologies, the required angles of attack to achieve a Vertical Force Balance (VFB) and a completely zero pitching moment conditions are considered. In addition, an analysis to optimise the nose configuration of the aircraft is performed. The mass flow rate throughout the scramjet as a function of the angle of attack is also presented in the CFD model in addition to the pressure, density, temperature and Mach fields. Before presenting the corresponding results, a comparison between the aerodynamic coefficients in terms of the angle of attack of both models is carried out in order to properly validate the CFD model. The paper clarifies the requirements needed to make sure that both oblique shock waves originating from the leading edge meet just at the scramjet inlet clarifying the advantages of fulfilling such condition.

The Satellite for Orbital Aerodynamics Research (SOAR) is a 3U CubeSat that has been designed to investigate the aerodynamic performance of different materials and perform demonstrations of aerodynamic attitude control manoeuvres in very low Earth orbit (VLEO). SOAR was deployed from the ISS on 14th June 2021 into a naturally decaying orbit and deorbited on 14th March 2022. This paper provides an overview of the operations performed during the mission and presents preliminary experimental results obtained from this spacecraft. SOAR was designed and launched within the frame of DISCOVERER, a Horizon 2020 project that aimed to support the development of a new class of commercially viable spacecraft operating in VLEO, i.e., orbits below 450 km in altitude. Operating in these lower altitude orbits has several benefits to the design of spacecraft, particularly for Earth observation and communications applications. However, development of spacecraft that can operate sustainably at these altitudes requires advancement in foundational technologies, for example atmosphere-breathing electric propulsion (ABEP) and novel aerodynamic materials. The primary aim of SOAR was to characterise the aerodynamic performance of different materials at very low altitudes and accomplished this task using a set of steerable fins that exposed different materials to the oncoming flow and an ion and neutral mass spectrometer (INMS) to provide in-situ measurements of atmospheric properties. SOAR was also designed to perform novel aerodynamic attitude control manoeuvres and measurements of thermospheric winds. Two of the materials carried to orbit were selected for their atomic oxygen erosion resistance and potential improvement in aerodynamic performance. The identification of such materials would allow for a reduction in the drag experienced in VLEO, the design of atmospheric intakes with greater efficiency used for ABEP, and implementation of enhanced aerodynamic attitude and orbit control. Ongoing ground-based experimentation seeks to further characterise the properties of such materials and to deepen our understanding of the physical interaction mechanisms that occur in the rarefied flow environment of VLEO.

[ES] Mejorar el rendimiento de los vuelos es un área que se encuentra actualmente bajo investigación debido a su relevancia para los costos económicos y ambientales. El concepto de ala morphing aborda este problema optimizando la forma aerodinámica del ala en cada una de las etapas de vuelo, que se está desarrollando gracias al progreso en la tecnología de materiales, aeroelasticidad y sistemas de control, siendo las deformaciones estructurales una preocupación importante. En este sentido, este trabajo recoge la información recopilada sobre medidas de deformación en alas morphing a escala fabricadas en PETG y metacrilato. Se han utilizado dos métodos de medición de deformaciones: galgas extensométricas y técnicas de correlación digital (DIC). Se ha utilizado una configuración con sensores de deformación integrados en un puente de Wheatstone con un Arduino para cuantificar las deformaciones de la piel del ala mientras cambia su forma en diferentes condiciones de vuelo simuladas en un túnel de viento. Paralelamente, también se han estimado las tensiones que sufre el ala morphing en cada una de estas condiciones con el software GOM Correlate, que analiza los procesos de deformación a partir de datos de vídeo de un patrón moteado en zonas localizadas de la piel. Ambos hallazgos se comparan y procesan para evaluar la plausibilidad de las aplicaciones reales de UAV., [EN] Improving flight performance is an area that is currently under investigation due to its relevance to economic and environmental costs. The concept of a morphing wing tackles this issue by optimizing the aerodynamic shape of the wing in each of the flight stages, which is being developed thanks to the progress in materials technology, aeroelasticity and control systems, being structural deformations an important concern. In this regard, this paper gathers the collected information about strain measurements on scaled morphing wings made of PETG and methacrylate. Two strain measurement methods have been used: strain gauges and digital correlation techniques (DIC). A set-up with strain sensors built in a Wheatstone bridge has been used with an Arduino to quantify the deformations of the skin of the wing while it shifts its form in different flight conditions simulated in a wind tunnel. In parallel, the strains suffered by the morphing wing in each of these conditions have also been estimated with the GOM Correlate software, which analyzes deformation processes from video data of a speckle pattern in localized areas of the skin. Both findings are compared and processed to evaluate the plausibility of real UAV applications.

ALF/ENGAER 139424-L Vasco Luís Martins Ferreira Coelho. Examination Committee: Chairperson: BGEN/EngEl 119923-E Rui Fernando da Costa Ferreira; Supervisor: MAJ/EngAer 131603-G Joao Vítor Aguiar Vieira Caetano, Dr. Frederico José Prata Rente Reis Afonso; Member of the Committee: Prof. Dr. Afzal Suleman Esta tese está integrada num projeto de desenvolvimento de um veículo aéreo não tripulado capaz de efetuar descolagem e aterragem vertical, e tendo hidrogénio como principal fonte de energia utilizando para tal uma célula de combustível. A dissertação foca-se nas fases de desenvolvimento preliminar e detalhada no que diz respeito a estudos aerodinâmicos e desempenho em voo. A fase preliminar abrange a conceção da asa e da cauda, recorrendo ao software XFLR5, em conjunto com uma estimativa da resistência aerodinâmica total da aeronave, recorrendo a expressões semi-empíricas. Para a análise detalhada, foi utilizado o software de mecânica de fluidos computacional Fluent. A escolha do modelo de turbulência SST, em conjunto com o modelo de transição y_Re0 , é validada pelas simulação 2D do perfil SG6042, apresentando resultados consistentes com os dados experimentais. A polar aerodinâmica da asa é obtida através da simulações 3D da mesma para vários ângulos de ataque. Por forma a melhorar as propriedades aerodinâmicas da asa, foi aplicada torção à ponta da asa, movendo a região inicial da perda da ponta da asa para a raiz. O impacto do sistema de propulsão vertical na resistência aerodinâmica em voo cruzeiro é avaliado através da realização de testes em túnel de vento e simulações em Fluent. Simulações de toda a aeronave concluem que, dependendo do alinhamento dos rotores, a resistência aerodinâmica da aeronave varia entre 16.32 e 19.22 N para voo cruzeiro, resultando num tempo total de voo entre 3H05 e 3H25. This thesis is part of a project to design an unmanned aerial vehicle capable of performing vertical take-off and landing, and having hydrogen as its main energy source by using a fuel cell. The present dissertation is focused on the preliminary and detailed design phases regarding aerodynamics and flight performance studies. The preliminary phase encompasses the wing and tail design, with the aid of XFLR5, together with an estimate of the total aircraft drag by resorting to semi-empirical expressions. A longitudinal static stability analysis is conducted, and the unmanned aerial vehicle characteristics are presented after the preliminary phase of the project. For the detailed analysis, Fluent was chosen as the computational fluid dynamics software to be used. 2D simulation over the SG6042 wing airfoil validated the choice of the SST turbulence model, coupled with the y_ Re0 transition model, as the results were consistent with experimental data. The drag polar of the wing is obtained by simulating the 3D wing at various angles of attack. To enhance the wing aerodynamic properties, twist was given to the wingtip, moving the stall region from the wingtip to the root. The impact of the vertical propulsion system on the drag at cruise is assessed by performing wind tunnel tests and simulations on Fluent. Simulations of the entire aircraft conclude that, depending on the stopping position of the rotors, the drag of the aircraft varies between 16.32 and 19.22 N for cruise, which results in a total flight time between 3H05 and 3H25. N/A

[ES] Las resoluciones numéricas mediante métodos de cálculo DNS de problemas de Mecánica de Fluidos son el futuro de la Aerodinámica ya que permiten obtener toda la información del campo que se estudia. Sin embargo, actualmente no se dispone de la capacidad computacional, en todo el mundo, que sea capaz de suplir las necesidades de este método de cálculo para una simple ala. El objetivo principal de este proyecto es mejorar las resoluciones DNS que se tiene en la actualidad para así acercar este modelo de cálculo a una realidad en las simulaciones en el plano de la Ingeniería Aeronáutica. Se va a realizar modificaciones en el código LISO con el fin de dotarle de cierta versatilidad para poder enfrentarse a problemas de capa límite o turbulencia de pared. Esto permitirá alcanzar valores de Reτ numéricos más grandes que los que se ha podido obtener hasta ahora. Las simulaciones que se ha realizado se han sido ejecutadas en un primer momento en el supercomputador de la UPV con el modelo secuencial del que se dispone, las simulaciones del modelo paralelizado se deberán en el SuperMUC del CLS ya que se requiere de millones de horas de cálculo distribuidas entre distintos servidores, [EN] The numerical resolutions by means of DNS calculation methods of Fluid Dynamics problems are the future of Aerodynamics since they allow obtaining all the information of the field under study. However, there is currently no computational capacity worldwide that is capable of meeting the needs of this calculation method for a simple wing. The main objective of this project is to improve the DNS resolutions that are currently in place in order to bring this calculation model closer to a reality in simulations in the domain of Aeronautical Engineering. Modifications will be made to the LISO code in order to give it some versatility to be able to face problems of boundary layer or wall turbulence. This will allow reaching numerical Reτ values larger than those that have been obtained so far. The simulations that have been carried out have been initially run on the UPV’s supercomputer with the available sequential model, the parallelized model simulations must been run on the CLS’s SuperMUC since it requires millions of hours calculation distributed among different servers., [CA] es resolucions numèriques mitjan¸cant mètodes de càlcul DNS de problemes de mecànica de fluids són el futur de la Aerodinàmica ja que permeten obtenir tota la informació de camp que s’estudia. Actualment, però, no es disposa de la capacitat computacional, en tot el món, que sigui capaç de suplir les necessitats d’aquest mètode de càlcul per a una simple ala. L’objectiu principal d’aquest projecte és millorar les resolucions DNS que es té en l’actualitat per així apropar aquest model de càlcul a una realitat en les simulacions en el pla de l’Enginyeria Aeronàutica. Es va a realitzar modificacions en el codi LISO amb la finalitat de dotar-li de certa versatilitat per poder enfrontar-se a problemes de capa límit o turbulència de paret. Això permetrà assolir valors de Reτ numèrics més grans que els que s’ha pogut obtenir fins ara. Les simulacions que s’ha realitzat s’han estat executades en un primer moment en el supercomputador de la UPV amb el model seqüencial de què es disposa, les simulacions de el model paral·lelitzat es deuran en el SuperMUC de l’CLS ja que es requereix de milions d’hores de càlcul distribuïdes entre diferents servidors

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In the last years, the Formula 1 competition is becoming more an engineers sport ratherthan a pilots one since it seems like who ever has the best racing car, wins without manydifficulties. One of the main reasons for that are found in the complex aerodynamic de-signs of the cars that causevery significant turbulence on the flow. Current carsare designed to preform at its maximum potential when receiving a clean flow under freestream conditions. But this scenario is not the one we find when a car is trying to overtakeanother car. When this happens, the chasing car is receiving a turbulent flow provokedby the leading car and, consequently, it suffers from adrastic aerodynamic downforceloss, which is specially essential in curves, when cars need as much downforce as possiblein order to gain adherence and be able to take the curve at a higher speed. The FIA(F ́ed ́eration Internationale de l’Automobile) has already noticed that and, consequently,in 2022 it will implement one of the most revolutionaries changes in terms of aerodynamicregulations, which are mainly based on a simplified aerodynamic package that will reducethe turbulence of the cars and therefore will allow easier overtakes and a closer racingwhere the most talented pilot will be able to shine.The aim of present study is to evaluate the aerodynamic performance of a 2017 F1 carmodel in curves by means of a CFD study under both free stream flow and turbulent flowconditions. Once the desired results are obtained, a comparison between the performancesin both condition will be done in order to be able to quantify how the wake of the firstcar affects the chasing car and this waydiscuss if the new future regulation areindispensable.

Diffusers and the floor ahead of them create the majority of the downforce a vehicle creates. Outside motorsports, the diffuser is relatively unused, although its interaction with the ground is a consistent field of study owing to the aerodynamic benefits. The diffuser flow behavior is governed by three fluid-mechanical mechanisms: ground interaction, underbody upsweep, and diffuser upsweep. In addition, four different flow regimes appear when varying ride height, the vortices of which have great importance on downforce generation. The present study focuses on the diffuser’s fluid-dynamic characteristics undertaken within an academic framework with the objective of finding and understanding a high level of performance in these elements. Once the functioning of diffusers has been analyzed and understood, a new configuration is proposed: rear vertical airfoil endplates. The aim of the paper is to study the effect in performance of vertical airfoil endplates on diffusers in vehicle aerodynamics in a simplified geometry. The candidate to this geometry is the inversed Ahmed body, a geometry that is used as a model that simulates the flow behavior of car diffusers. Three different diffuser configurations are performed, namely 0° diffuser, 25° diffuser, and in the third case vertically installed rear vertical airfoil endplates are added to the 25° diffuser Ahmed body to change the flow field. These analyses are carried out by using open-source CFD simulation software OpenFOAM. An inlet velocity of 20 m/s is considered, as this is a typical velocity when cornering in motorsport. It is concluded that the 25° diffuser configuration generated more downforce than the 0° diffuser, which makes sense as the aim of adding a diffuser is to increase the amount of downforce produced. In addition, and as a result of the newly proposed configuration, the 25° diffuser Ahmed body with the vertical airfoil endplates emerges in a substantial increase of downforce thanks to the low-pressure zone generated at the back of the body.

The operation of satellites in very low Earth orbit (VLEO) has been linked to a variety of benefits to both the spacecraft platform and mission design. Critically, for Earth observation (EO) missions a reduction in altitude can enable smaller and less powerful payloads to achieve the same performance as larger instruments or sensors at higher altitude, with significant benefits to the spacecraft design. As a result, renewed interest in the exploitation of these orbits has spurred the development of new technologies that have the potential to enable sustainable operations in this lower altitude range. In this paper, system models are developed for (i) novel materials that improve aerodynamic performance enabling reduced drag or increased lift production and resistance to atomic oxygen erosion and (ii) atmosphere-breathing electric propulsion (ABEP) for sustained drag compensation or mitigation in VLEO. Attitude and orbit control methods that can take advantage of the aerodynamic forces and torques in VLEO are also discussed. These system models are integrated into a framework for concept-level satellite design and this approach is used to explore the system-level trade-offs for future EO spacecraft enabled by these new technologies. A case-study presented for an optical very-high resolution spacecraft demonstrates the significant potential of reducing orbital altitude using these technologies and indicates possible savings of up to 75% in system mass and over 50% in development and manufacturing costs in comparison to current state-of-the-art missions. For a synthetic aperture radar (SAR) satellite, the reduction in mass and cost with altitude were shown to be smaller, though it was noted that currently available cost models do not capture recent commercial advancements in this segment..., Comment: 23 pages, 6 figures, Accepted for publication in Acta Astronautica (2021-07-03)

The vortex induced vibrations (VIVs) of a pivoted cylinder with finite height have been numerically investigated. A mathematical model is introduced and described, and the resulting equations are numerically solved for low Reynolds number Re = 100, 200 and several combinations of the governing parameters. Results on the solid body trajectories, the maximum amplitude of the oscillations, the hydrodynamic force coefficients, the wake structure, and details on the vortex shedding near the cylinder are presented and discussed. The numerical results compare reasonably well with the canonical system of VIV of two-degrees of freedom circular cylinder in the laminar regime. Also, qualitative similarities with closely related VIV systems at larger Re suggest interesting lines of future research. Analytical approximations for limiting cases are done and an excellent agreement with the numerical results is obtained. This work was partially financially supported by the “Ministerio de Economıa y Competitividad, Secretarıa de Estado de Investigacion, Desarrollo e Innovacion,” Spain (Ref. TRA2017-88508-R). D. Pastrana acknowledges the support of the CONACyT-SENER graduate fellowship program to study abroad 278102/439162. J. C. Cajas acknowledges the financial support of UNAM through the project PAPIIT-IA106120 and the access to supercomputing resources at Miztli: LANCAD-UNAM-DGTIC-379.

Through the means of temperature variations of the aerofoil surface this report aimed to investigate and enhance the aerodynamic efficiency of micro air vehicles. Through the process of heating the lower edge of the aerofoil nose and cooling the upper leading edge of the nose surface, an increase of Lift/Drag coefficient was observed. The focus of this research lies in the computational investigation of this affect on small scale high cambered aerofoils at a range of zero angle of attack at moderate Reynolds number flow