Search

The controls on the development of submarine channel sinuosity are contested: slope gradient and Coriolis forcing have both been recognized as key governing factors: gradient via an inverse relationship (low sinuosity at high slope and vice versa), and Coriolis forcing through its effect on sedimentation patterns (reducing lateral bend migration, and hence sinuosity development, at high latitudes and/or in large channels). Using theoretical models to calculate the bulk properties of channelized turbidity currents, this study investigates the joint role of the Coriolis force and parameters including channel size, downchannel slope and turbidity current properties in the development of submarine channel sinuosity. Model validation is undertaken through the comparison of the calculated turbidity current tilting against the measured tilting of channel levees in the Northwest Atlantic Mid‐Ocean Channel; this approach is then used to evaluate the controls on channel sinuosity in nine other modern seafloor channels. The results indicate that the Coriolis force only becomes significant when the size of the channel, the slope gradient and flow conditions are within appropriate ranges instead of solely being dependent on latitude. Thus, thick and dense (≥1% bulk sediment concentration) flows traveling within steep‐gradient, small‐scale channels were shown to be relatively less susceptible to flow modification by Coriolis forcing even at high latitudes. On the other hand, thin and dilute (≪1% bulk sediment concentration) flows in shallow‐gradient, large‐scale channels showed susceptibility to Coriolis forcing at all latitudes. These results offer new insights into submarine channel evolution and intra‐channel sedimentation patterns. Plain Language Summary: Sediments are widely distributed in the oceans by underwater currents akin to powder snow avalanches. These "turbidity currents" may sculpt the sea floor to build submarine channels which, like rivers, may range in sinuosity from being virtually straight to highly sinuous. Several competing controls have been suggested to explain this variation. Some argue that slope is most important, with low sinuosity channels forming on high angle slopes and vice versa. Others claim that the Coriolis force, which affects flows moving across a rotating surface (such as the Earth), is the main control ‐ either via latitude alone (with high sinuosity channels restricted to lower latitudes) or only affecting channels that are large enough. To test these ideas we developed a new numerical modeling approach that looks at the combined effects of channel axis gradient, channel size and flow conditions. By modeling the tilt of turbidity currents flowing around bends we show that single factors cannot be used to explain channel sinuosity. The model is tested with real world data. Although sinuosity is generally greater at low latitudes there are exceptions; variations across a range of controlling factors can produce channels of any sinuosity at any latitude. Key Points: We present a novel methodology to assess the contested controlling factors on the development of sinuous channelsDeep and dense flows that pass through small channels in steep slopes, regardless of the latitude, promote sinuosityDilute and shallow flows that pass through large channels in low gradient systems hinder sinuosity development at any latitude [ABSTRACT FROM AUTHOR]

The moving blades in a circular path have many industrial applications, in more modern turbo machines, such as jet engine compressors, the flow conditions are completely incompressible. On the other hand, the 2D study of the flow around these blades, which shows many characteristics of the flow and simplifies the matter, is usually unavoidable. In this regard, the simulation methods LES and RANS, in order to simulate the flow around the NACA0012 airfoil, different modes of fixed and rotating airfoil with different angles of attack and 3D impeller mode have been implemented. The lift coefficient, drag coefficient, torque, and mass flow of S-A, RNG, SST, RSM, and LES models are compared. The net mass rate will be different in the above methods. In RANS methods, the value of the net mass rate is negative; that is, loss of mass rate occurs, but in the LES method, the value of the net mass rate is positive. The highest net mass rate is related to the LES method, and in RANS models, the reverse flow is observed. According to the results, the effects of body forces in energy equation or thermal dissipation under circular motion are important in comparison with experimental data. A comparison of fixed and rotating airfoil lift coefficient diagrams with the LES model shows that the lift coefficient in a fixed airfoil is two times relative to a rotating airfoil. Also, the torque on the impeller, compared with different turbulent models, varies from 88381 to 172116.

Gyroscopes are devices used for orientation determination however mechanical gyroscopes are used for orientating and balancing via gyroscopic torque. This torque is generated by the precession speed given to the rotating objects from one of the axes other than the rotation axes. In this study, the gyroscopic torque was calculated using dynamic analysis onto a single flywheel mechanical gyroscope design created. Free vibration frequencies were determined by modal analysis. Dynamic responses for the movement of the gyroscope with a flywheel, which is mounted vertically and balances the weight torque, are investigated on the basis of classical (Newtonian) mechanics. When the flywheel rotates in the range of 0-250 rad/s, it does not correspond to any natural frequency. Torque of 0.468 Nm is offset by a precession velocity of 0.922 rad/s. Nutation oscillations disappears when torsional damping is given to the joint where the gyroscope is attached to the ground. The free vibration frequencies change in the damped state. [ABSTRACT FROM AUTHOR]

Planets and stars have liquid layers that can support internal gravity waves and inertial waves respectively restored by the buoyancy and Coriolis forces. Both types of waves are excited by tides, leading to resonantly amplified dissipation. We review the theoretical formalism to compute these resonances and present some challenges and methods to overcome them. [ABSTRACT FROM AUTHOR]

Introduction: Habituation to motion has therapeutic applications for motion sickness desensitization and rehabilitation of patients with vestibular disease. Less attention has been devoted to the opposite process: sensitization., Methods: Subjects (N = 50) were randomly allocated to four sequences: Baseline visual stimulus; then 15 min of time gap; cross-coupled motion (C-C) or a Control condition; then a time gap of 15 min or 2 h; then a retest visual stimulus. Motion exposures were for 10 min or until moderate nausea, whichever was sooner. The visual stimulus was a scene rotating in yaw at 0.2 Hz with superimposed "wobble". C-C was whole-body rotation on a turntable with eight 45° head tilts during each 30-s period. Control was head tilt without rotation. Rotational velocity was incremented in staircase steps of 3° · s-1 every 30 s., Results: Groups were equivalent for Total Motion Sickness Symptom scores elicited by the first visual stimulus (combined: mean ± SD 10.8 ± 8.4). C-C produced greater Total Symptoms (20.3 ± 6.8) than Control (3.1 ± 3.7). Subjects recovered subjectively from C-C before retest of visual stimulus. For the retest visual stimulus, Total Symptoms were higher following C-C (15.1 ± 9.0) than following Control (8.3 ± 7.1) for both the 15 min and 2 h retests. Sickness ratings (SR) mirrored these effects of C-C., Discussion: C-C motion sensitized subsequent responses to visual stimulation up to 2 h later. Sensitization of visual stimulation crossed modalities and appeared subconscious since it occurred despite subjective recovery from C-C. For some individuals, a previously relatively innocuous visual stimulus became nauseogenic on retest. The results have implications for the use of visual technologies within hours of exposure to provocative motion. Golding JF, Alund D, Gresty MA, Flynn MB. Sensitization of visually induced motion sickness by prior provocative physical motion. Aerosp Med Hum Perform. 2024; 95(10):741-748.

A two-dimensional vertically integrated shallow water equation in the Cartesian coordinate model is used to estimate the water level considering the impact of Coriolis force. The shallow water model equation was discretized by a finite difference method (FDM). Consider the forwarding of time and central space as a moderator of this discretization. The model approximates coastal boundaries, small islands, small rivers and complex tributaries by an accurate stair step representation. The model equations are solved by a static semi-implicit finite difference technique where a structured Arakawa C-grid system is used as the condition. A one-way nested scheme technique is used to incorporate complex land-sea interfaces such as small offshore islands and water depths with sufficient accuracy as well as decreasing the computational cost. A stable tidal condition was created by applying M2 tidal forcing with the largest tide along the southern open boundary of the Bay of Bengal. The model uses the Coriolis force as an external force that can affect water buoyancy. The main task is to analyse the effect of Coriolis force on water buoyancy. The described model was applied to simulate sea-surface elevation associated with the severe cyclone in April 1991 that strike on the east coast of Bangladesh. We have found a significant impact of Coriolis force on surge height. However, the model gives an accurate numerical estimate of surge height.

We numerically investigate the propagation of internal solitary waves under the Coriolis effect using a three-dimensional hydrodynamic model, which employs a periodic boundary condition in the transverse direction of propagation. As the Rossby number decreases, the group velocity and representative length of the wave train also decrease. Intriguingly, the speed of the waves inside the wave train equals the difference in group velocities between no rotation and rotation when the Rossby number is more than 3. Our energy analysis found that the kinetic energy must be greater than the potential energy. Moreover, the kinetic energy in the transverse direction is necessary for stable propagation of the wave train. The total and kinetic energies were confirmed to have lower attenuation rates as the Rossby number increased. In contrast, the potential energy had a lower attenuation rate for smaller Rossby numbers, suggesting that kinetic energy determines energy attenuation for such numbers. As for the real scale phenomena, the present results revealed that significant energy attenuation of the internal solitary waves due to the rotation can be expected in areas less than a nondimensional water depth of 0.84, and where the nondimensional longwave speed is less than 0.55. [ABSTRACT FROM AUTHOR]

As industry continues to embrace Industry 4.0, many sectors now seek to automate fraud detection to ensure reduced financial exposure. However, the data-driven models which are commonly used in the development of such ‘digital solutions’ rely on ‘supervised’ learning techniques which require high resolution datasets containing labelled instances of the specific fraudulent activity. In reality, applications such as engineering and manufacturing only have limited datasets which contain such information and recreating the physical conditions surrounding the fraudulent activity is often not practical or is illegal. This paper details a collaborative R&D project undertaken for the fuel bunkering industry; whereby data-driven models were designed to detect fraudulent activity during fuel transfer operations. Synthetic data generation was used to build up high resolution datasets based on field data which contained instances of fraud. The results demonstrate successful synthetic data generation and modelling techniques with high predictive accuracies.

This paper presents a comparative evaluation study of a newly developed mass flowmeter which combines a positive-displacement volumetric flowmeter and a densitometer, comparing its performance with a well-established Coriolis mass flow metering technology. The former which is a multiple-sensors measuring device shows a wider rangeability with a performance variation of within ±1 %over the whole measuring range, whereas the latter which is a single-sensor measuring device shows an excellent performance in its optimum measuring range but exhibits larger performance variation up to about±25 %near the bottom limit of its measuring range.

The group properties of the shallow‐water equations with the complete Coriolis force are the subject of this study. In particular, we apply the Lie theory to classify the system of three nonlinear partial differential equations according to the admitted Lie point symmetries. For each case of the classification problem, the one‐dimensional optimal system is determined. The results are applied for the derivation of new similarity solutions. [ABSTRACT FROM AUTHOR]

In this paper we present a $\mu $ -Coriolis mass flow sensor with differential capacitive readout, which can reduce the effect of common mode vibrations caused by external disturbances. The device consists of two silicon nitride micro-channel loops mechanically connected through two membranes. The sensor is actuated using Lorentz forces, inducing rotation of the sensor’s micro-channels. Coriolis forces of opposite sign are subsequently generated in the two channel loops. Thus, any common mode vibration can be distinguished from vibration induced by mass flow through the channels. Capacitive readout structures surround the sensor to detect these vibrations. A piezo-electric resonator is placed in close proximity to the sensor to generate artificial external disturbance. Flow measurements are executed to compare the differential readout method to a single ended readout with and without external disturbances. The flow sensitivity is unaffected. However, the mean deviation of the output signal is 60-70% lower when using the differential readout compared to single ended readout when external disturbances are induced. The effect of external disturbances on the zero flow stability is reduced by approximately 64% by using the differential readout. Full elimination of the effect is not possible due to non-linearity of the readout capacitors. Reducing non-linearity of the readout could further improve performance, e.g. by implementing (piezo-resistive) strain gauges on top of the micro-channel. [ABSTRACT FROM AUTHOR]

Due to growing importance of study of bio-fluids in rotational microfluidic platforms, discussion of flow of viscoplastic materials in such situations becomes very important. Bio-fluids also generally flow in soft channel microfluidic environment and therefore studying the effect of softness of channels on flow of such viscoplastic bio-fluids becomes critical. We, in the present study, investigate the effect of the rotation of the channel and yield stress of the fluid on the flow of viscoplastic material in a soft microchannel for three constitutive models viz. Bingham, Casson and Herschel–Bulkley models. It is found that the soft grafted layer, the channel rotation and the fluid yield stress play vital roles in determining the flow behaviour. We find that that larger rotational speeds tend to destabilize the flow. We also find the critical rotational speed for which secondary flow magnitude is maximum. We also find that this non-linear interaction between rotation of channel and fluid yield stress leads to the generation of multiple yield planes within the flow domain. Our study will help in obtaining good designs of rotational microfluidic platforms for studying bio-fluids with yield stress. [ABSTRACT FROM AUTHOR]

Annulus pipe conveying fluids have many practical applications, such as hydraulic control lines and aircraft fuel lines. In some applications, these tubes are exposed to high speeds. Normally, this leads to a vibration effect which may be of a catastrophic nature. The phenomenon is not only driven by the centrifugal forces, but an important role is played also by the Coriolis forces. Many theoretical approaches exist for a simple configuration or a complex three-dimensional configuration. Finite element models are tested. This paper provides a numerical technique for solving the dynamics of annulus pipe conveying fluid by means of the mono-dimensional Finite Element Method (FEM). In particular, this paper presents a numerical solution to the equations governing a fluid conveying pipeline segment, where a Coriolis force effect is taken into consideration both for fix and hinge constraint. [ABSTRACT FROM AUTHOR]

Detecting infectious aerosols is central for gauging and countering airborne threats. In this regard, the Coriolis® µ cyclonic air sampler is a practical, commercial collector that can be used with various analysis methods to monitor pathogens in air. However, information on how to operate this unit under optimal sampling and biosafety conditions is limited. We investigated Coriolis performance in aerosol dispersal experiments with polystyrene microspheres and Bacillus globigii spores. We report inconsistent sample recovery from the collector cone due to loss of material when sampling continuously for more than 30 min. Introducing a new collector cone every 10 min improved this shortcoming. Moreover, we found that several surfaces on the device become contaminated during sampling. Adapting a high efficiency particulate air-filter system to the Coriolis prevented contamination without altering collection efficiency or tactical deployment. A Coriolis modified with these operative and technical improvements was used to collect aerosols carrying microspheres released inside a Biosafety Level-3 laboratory during simulations of microbiological spills and aerosol dispersals. In summary, we provide operative and technical solutions to the Coriolis that optimize microbiological air sampling and improve biosafety. [ABSTRACT FROM AUTHOR]

In stratified flow, breaking of internal waves over slopes induces resuspension of bottom sediments and transport of mass. When internal waves shoal and break, flow dynamics and mass transport differ significantly according to whether the Coriolis force is included or neglected. Despite its importance, the currents generated by breaking internal Kelvin waves remain uninvestigated. Therefore, this study considers breaking of internal waves over a uniform slope under Coriolis with equivalent upper‐ and lower‐layer depths. Laboratory experiments, using a 6.0‐m rotating tank, were undertaken to visualize currents using particle image velocimetry. Experimental data validated a three‐dimensional fluid dynamics model, in which a phase‐averaged velocity (residual jet) was simulated to occur at the lateral wall (to the right) of the progressive internal Kelvin waves in the breaking zone, with the generation of an oblique downslope return flow (downdraft) under Coriolis. The geostrophic balance drove the residual jet, and the equation for estimating the residual current, due to the jet, was formulated and was discussed by referring a coastal jet in Lake Erie. The results provide insight on mass transport in lakeshore and coastal zones.Plain Language Summary: The key idea of the present study is the “residual jet” which occurs at the lateral wall on the right side of the progressive internal Kelvin waves due to breaking over a uniform slope. We conducted laboratory experiments by using a rotating tank, and internal Kelvin wave breaking was visualized by using particle image velocimetry (PIV) method. Also, using a three‐dimensional fluid dynamics model, a residual jet was demonstrated to occur with the generation of an oblique downdraft running down the slope under Coriolis, which was verified through the laboratory experiments. We found that the geostrophic balance drives a residual jet, and the equation for estimating the residual current, due to the jet, was formulated and was discussed by referring a coastal jet in Lake Erie. Therefore, the paper will provide the oceanography communities with a new understanding of the effect of internal Kelvin wave breaking, and the associated residual currents, on long‐term mass transport.Key Points: A residual jet was shown to occur at the lateral wall of a cyclonically propagating internal Kelvin wave breaking over a uniform slopeThe residual jet occurred under a geostrophic balance and generated an oblique downdraft running down the slope, due to CoriolisAn equation was formulated for estimating the residual current due to the residual jet [ABSTRACT FROM AUTHOR]

In recent years, the Coriolis mass flow meters (CMF), devices based on the Coriolis effect over a vibrating pipe, have developed better metrological performance and they are now a reasonable alternative for the custody transfer measurements. Nowadays, many custody transfer operations require measurement of the net volume (volume measured at a certain reference temperature) and, therefore, it is not feasible to use the CMF as a mass flow meter. However, the actual CMF can be used as net volume meters because they have special equipment to measure density and temperature, and a flow computer. In this work, firstly a mathematical simplification of the physical model is proposed for the CMF. We part from the dimensional analysis of the flow-phase relationship produced by the Coriolis force, the main physical principle behind these devices. A simplified formula is obtained and it permits identifying the magnitudes of influence of the CMF as a mass meter. Secondly, its metrological properties are characterized. For such purpose, a 4" straight tube commercial meter has been calibrated in volume, in the 50 to 165 m3/h range against a standard container and a bidirectional prover, employing gas oil and kerosene (JET-A1). These calibrations have turned out to be compatible with the ones performed by the manufacturer in mass and using water. Then it is verified that the CMF fulfills the requisites of the legal metrology: maximum error allowed, linearity and repeatability. Skewness is observed in the relative error (expressed in %) of the CMF and it has been researched to be due to systematic effects related to constructive parameters of the meter. Lineal correlation is verified between relative error and temperature, and between relative error and flow rate, with negative slopes of −0.03% °C−1 and −0.001% h/m3 respectively. • A simplified physical model for Coriolis mass flow meter (CMF) is obtained. • It permits identifying the main magnitudes of influence of the CMF. • Metrological properties are characterized by calibrating a commercial CMF against a bidirectional prover and against a standard container. • Custody transfer operations based on volume measurements can be performed correctly through a CMF. [ABSTRACT FROM AUTHOR]

This study assessed the collection efficiency (CE) of two popularly used sampling devices (BioSampler and Coriolis sampler) for fungal aerosols. Phosphate‐buffered saline (PBS) supplemented with or without surfactant (Tween‐20, Tween‐80, or Triton X‐100) and antifoam agent was prepared and used as collection liquids. The agar impactor (BioStage) was simultaneously operated with liquid‐based samplers to collect fungi from seven sites located at a university building, public library, and animal farming. Fungal concentrations determined by liquid samplers were divided by those by BioStage, and the ratio values represented CE. Results indicate that the CE of BioSampler was superior to that of Coriolis (P = 0.0001) and the PBS containing surfactant collected fungi better than that without surfactant (P < 0.0001), whereas antifoam agent showed no influence (P = 0.8). Moreover, fungal concentrations determined by BioSampler with surfactant‐added PBS were statistically indifferent from those by BioStage (P > 0.05) with a Spearman correlation coefficient of 0.81‐0.83 (P < 0.01). In addition to sampler and collection liquid, sampling location was also identified as a significant CE factor (P = 0.006), implying potential influences by fungal genera in the studied fields. Overall, BioSampler with surfactant‐supplemented PBS (eg, Triton X‐100) is recommended considering the great CE and compatibility with a variety of analytical assays. [ABSTRACT FROM AUTHOR]

The impact of the Coriolis force on the long distance wake behind wind farms is investigated using Large Eddy Simulations (LES) combined with a Forced Boundary Layer (FBL) technique. When using the FBL technique any mean wind shear and turbulent fluctuations can be added with body forces. The wind shear can also include the mean wind veer due to the Coriolis force. The variation of the Coriolis force due to local deviations from the mean profile, e.g., from wakes, is not taken into account in the FBL. This can be corrected for with an extra source term in the equations, hereon defined as the Coriolis correction. For a row of 4 turbines it is shown that the inclusion of the wind veer turns the wake to the right, while including the Coriolis correction turns it to the left. When including both wind veer and Coriolis correction the impact of wind veer dominates. For an idealized farm to farm interaction case, two farms of 4 ∗ 4 turbines with 6 km in between, it can be seen that when including wind veer and the Coriolis correction a approximately 3% increase in the relative production for a full wake direction can be seen and only a slightly smaller increase can be seen when including only wind veer. The results indicate that FBL can be used for studies of long distance wakes without including a Coriolis correction but efforts need to be taken to use a wind shear with a correct mean wind veer. [ABSTRACT FROM AUTHOR]

Annulus pipe conveying fluids have many practical applications, such as hydraulic control lines and aircraft fuel lines. In some applications, these tubes are exposed to high speeds. Normally, this leads to a vibration effect which may be of a catastrophic nature. The phenomenon is not only driven by the centrifugal forces, but an important role is played also by the Coriolis forces. Many theoretical approaches exist for a simple configuration or a complex three-dimensional configuration. Finite element models are tested. This paper provides a numerical technique for solving the dynamics of annulus pipe conveying fluid by means of the mono-dimensional Finite Element Method (FEM). In particular, this paper presents a numerical solution to the equations governing a fluid conveying pipeline segment, where a Coriolis force effect is taken into consideration both for fix and hinge constraint.

This paper describes fluid classification methods using machine learning applied on a microfabricated Coriolis mass flow sensor with integrated pressure sensors. The latter are positioned upstream and downstream of the Coriolis mass flow sensor, which enables the measurement of the viscosity-dependent pressure drop. The Coriolis mass flow sensor itself is particularly sensitive to the mass flow and density of the fluid. Five different liquids (nitrogen, water, isopropanol, ethanol and acetone) are applied to the sensor system in different combinations of mass flow rate, pressure and temperature. For each combination, the raw signals from all sensors are amplified, demodulated, digitized, sampled and stored. Then BiLSTM and CNN neural networks were trained and tested by using train-test split validation and K-fold cross-validation. With both methods, the classification accuracy is determined using a different part of the dataset than for learning. For mass flow rates up to 5 g/h, pressures between 4 bar and 6 bar and temperatures between 288 K and 308 K. BiLSTM performs best with a cross-validated accuracy of 77% up to 100%, dependent on the inclusion of low-flow data. [Display omitted] • Fluid classification with microfabricated flow/pressure sensors is realized using AI. • Classification proved to be mostly independent of the fluid state (e.g., flow). • BiLSTM has a cross-validated accuracy of 77% up to 100% (for high flows). [ABSTRACT FROM AUTHOR]

This paper presents a μ -Coriolis mass flow sensor with resistive readout. Instead of measuring a net displacement such as in a capacitive readout, a resistive readout detects the deformation of the suspended micro-fluidic channel. It allows for actuation at much higher amplitudes than for a capacitive readout, resulting in correspondingly larger Coriolis forces in response to fluid flow. A resistive readout can be operated in two actuation vibrational modes. A capacitive readout can only be operated in one of these two modes, which is more sensitive to external disturbances. Three types of devices have been realized. We present measurement results for all three devices. One device clearly outperforms the other two, with a flow sensitivity of 2.22 °/(g·h−1) and a zero-flow stability of 0.02 g·h−1 over 30 min. Optimization of the metal strain gauges and/or implementation of poly-Silicon strain gauges could further improve performance.

In this work, an arbitrary order augmented WENO-ADER scheme for the resolution of the 2D Shallow Water Equations (SWE) with geometric source term is presented and its application to other shallow water models involving non-geometric sources is explored. This scheme is based in the 1D Augmented Roe Linearized-ADER (ARL-ADER) scheme, presented by the authors in a previous work and motivated by a suitable compromise between accuracy and computational cost. It can be regarded as an arbitrary order version of the Augmented Roe solver, which accounts for the contribution of continuous and discontinuous geometric source terms at cell interfaces in the resolution of the Derivative Riemann Problem (DRP). The main novelty of this work is the extension of the ARL-ADER scheme to 2 dimensions, which involves the design of a particular procedure for the integration of the source term with arbitrary order that ensures an exact balance between flux fluctuations and sources. This procedure makes the scheme preserve equilibrium solutions with machine precision and capture the transient waves accurately. The scheme is applied to the SWE with bed variation and is extended to handle non-geometric source terms such as the Coriolis source term. When considering the SWE with bed variation and Coriolis, the most relevant equilibrium states are the still water at rest and the geostrophic equilibrium. The traditional well-balanced property is extended to satisfy the geostrophic equilibrium. This is achieved by means of a geometric reinterpretation of the Coriolis source term. By doing this, the formulation of the source terms is unified leading to a single geometric source regarded as an apparent topography. The numerical scheme is tested for a broad variety of situations, including some cases where the first order scheme ruins the solution. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adequate instrument scanning is considered an important countermeasure against spatial disorientation (SD). Remarkably, literature on the relation between SD and pilots' visual scanning is scarce. The objective of this simulator study was to investigate the influence of SD on pilots' visual scanning and flight performance. METHODS: In a ground-based SD simulator, 10 novice military pilots were asked to manually fly 3 circuits. Unknowingly to the pilots, the final circuit contained one visual and four vestibular SD events. Simulator motion, flight performance, pilots' gaze direction, and control inputs were recorded and analyzed. Afterwards the pilots filled in a questionnaire about their recognition of events. RESULTS: Three of the five SD events significantly affected pilots' flight performance and gaze behavior. First, the false horizon during the cloud leans induced an unintended roll rate, 0.41 ± 0.36° ⋅ s-1 when the pilots were looking out the window. Second, the Coriolis illusion caused a 0.44 ± 0.18s delay in the first glance to the attitude indicator and triggered an unintended roll rate, 1.25 ± 1.33° ⋅ s-1, and bank angle deviation of 3.4 ± 3.7° during the coordinated turn. Third, the somatogravic illusion affected pilots' pitch inputs on the stick, but this seems to be confounded by inaccurate simulation of the illusion. DISCUSSION: This study provides direct experimental evidence that SD can evoke inappropriate control inputs and can influence the pilots' scanning behavior, even when SD is not recognized. We conclude that gaze tracking provides useful feedback on the pilot's instrument scan during SD simulator training when using appropriate scenarios and simulator motion. [ABSTRACT FROM AUTHOR]

The present work investigates the free vibration behavior of double-tapered functionally graded beams rotating in thermal environment, using an improved mathematical model. The functional gradation for ceramic–metal compositions, following power-law, is considered to be symmetric with respect to the mid-plane, leading to metal-rich core and ceramic-rich outer surfaces of the beam. The temperature dependence of the material properties are considered using Touloukian model. The nonlinearity in strain–displacement relationships for both the axial and transverse shear strains are considered. Firstly, the governing equations for deformed beam configuration under time-independent centrifugal loading are obtained using minimum total potential energy principle, and the solution is obtained following Ritz method. Then the free vibration problem of the centrifugally deformed beam is formulated employing Lagrange’s principle and considering tangent stiffness of the deformed beam configuration. Coriolis effect is considered in the mathematical model, and the governing equations are transformed to the state-space for obtaining an eigenvalue problem. The results for the first two modes of both chord-wise and flap-wise vibrations are presented in nondimensional plane to show the effects of taperness parameter, root-offset parameter, volume fraction exponent, operating temperature, and functionally graded material composition. The results in comparative form are presented for both temperature-dependent and temperature-independent material properties. [ABSTRACT FROM AUTHOR]

Vibrational states of trans -acrolein (propenal) between 1020 and 1200 cm −1 are analyzed using high-resolution infrared spectra obtained at the Canadian Light Source synchrotron radiation facility. The one fundamental in this range, ν 10 (C-C stretch vibration) is found to be strongly mixed with a combination vibration ν 14 + ν 18 by a Fermi-type interaction. Five additional states are directly observed via hot, combination, and overtone bands: ν 11 + ν 18 , ν 16 + ν 18 , ν 15 + ν 18 , 2ν 12 , and 2ν 17 . These seven vibrational states are analyzed in a large multi-state fit, along with nine more states which are not directly observed but which affect the observed states by means of many perturbations. Though this fit is cumbersome, incomplete, and not unique, it can account for 3668 out of 3835 assigned lines with an average error of less than 0.0004 cm −1 . [ABSTRACT FROM AUTHOR]

The turbulent velocity field in a rotating rib-roughened channel is studied by means of incompressible Large Eddy Simulations (LES). The computations are validated against Particle Image Velocimetry (PIV) measurements performed in the symmetry plane of an experimental model of the same geometry. The present simulations consider the effect of the Coriolis force on a periodic section of low aspect ratio (AR = 0.9) and one rib-roughened wall. The Reynolds number based on the bulk velocity and the hydraulic diameter is fixed to 15,000, whereas the rotation number is set to 0, 0.31 and 0.77. Beyond the analysis of the Coriolis force influence on the shear layer stability, the present simulations allow to characterize the stream-wise secondary flows that redistribute the momentum through the cross-section at the different rotation numbers, the temperature distribution, and the resulting heat transfer on the wall. The flow structure is similar at rotation numbers equal to 0.31 and 0.77 when the channel rotates in the clockwise direction, with reduced turbulence and heat transfer on the ribbed wall, which acts as leading side. Only minor differences in the secondary flows and mean velocity profiles are observed due to the different magnitude of the Coriolis force. On the other hand, it has been observed that the secondary flow structure differs significantly when the rotation number is increased from 0.30 to 0.77 under counter-clockwise rotation. In particular, Taylor-Görtler vortices are observed together with the Coriolis-induced secondary flows at the maximum rotation rate, leading to a redistribution of the mean and turbulent velocity fields, as well as a significant change in the heat transfer distribution. [ABSTRACT FROM AUTHOR]

We present results from laboratory experiments that simulate the effects of periodically varying discharge on buoyant coastal plumes. Freshwater is discharged into a two meter diameter tank filled with saltwater on a rotating table. The mean inflow rate, tank rotation period and density of the ambient salt water are varied to simulate a range of inflow Froude and Rossby numbers. The amplitude and the period of the inflow modulation are varied across a range that simulates variability due to tides and storms. Using the optical thickness method, we measure the width and depth of the plume, plume volume and freshwater retention rate in the plume. With constant discharge, freshwater is retained in a growing anticyclonic bulge circulation near the river mouth, as observed in previous studies. When the discharge is varied, the bulge geometry oscillates between a circular plume structure that extends mainly in the offshore direction, and a compressed plume structure that extends mainly in the alongshore direction. The oscillations result in periodic variations in the width and depth of the bulge and the incidence angle formed where the bulge flow re-attaches with the coastal wall. The oscillations are more pronounced for longer modulation periods, but are relatively insensitive to the modulation amplitude. A phase difference between the time varying transport within the bulge and bulge geometry determines the fraction of the bulge flow discharged into the coastal current. As a result, the modulation period determines the variations in amount of freshwater that returns to the bulge. Freshwater retention in the bulge is increased in longer modulation periods and more pronounced for larger modulation amplitudes. [ABSTRACT FROM AUTHOR]

Previous work has described the use of Coriolis mass flow metering for multiphase flows, with applications in the oil and gas industry. This paper describes the development and testing of a Coriolis two-phase flow metering solution for nitrogen/synthetic oil mixtures with viscosities ranging from 50 cSt to 500 cSt, and with Gas Volume Fractions (GVFs) ranging from 0% to 90%. Formal trials took place at the UK National Flow Laboratory. A single synthetic oil was used; its viscosity was adjusted by controlling temperature. The results show that Coriolis metering is well suited to high viscosity oil/gas mixtures: in the formalized trials, mass flow errors for gas were mostly within 5% and for liquid were mostly within 2.5%. Achieving this accuracy up to 90% GVF represents an advance on previous work, which has been limited to around 50% GVF for low viscosity oils in two-phase and three-phase mixtures. [ABSTRACT FROM AUTHOR]

The impact of the Coriolis force on the long distance wake behind wind farms is investigated using Large Eddy Simulations (LES) combined with a Forced Boundary Layer (FBL) technique. When using the FBL technique any mean wind shear and turbulent fluctuations can be added with body forces. The wind shear can also include the mean wind veer due to the Coriolis force. The variation of the Coriolis force due to local deviations from the mean profile, e.g., from wakes, is not taken into account in the FBL. This can be corrected for with an extra source term in the equations, hereon defined as the Coriolis correction. For a row of 4 turbines it is shown that the inclusion of the wind veer turns the wake to the right, while including the Coriolis correction turns it to the left. When including both wind veer and Coriolis correction the impact of wind veer dominates. For an idealized farm to farm interaction case, two farms of 4 ∗ 4 turbines with 6 km in between, it can be seen that when including wind veer and the Coriolis correction a approximately 3% increase in the relative production for a full wake direction can be seen and only a slightly smaller increase can be seen when including only wind veer. The results indicate that FBL can be used for studies of long distance wakes without including a Coriolis correction but efforts need to be taken to use a wind shear with a correct mean wind veer.

The dynamical behaviors of pipes containing pulsating fluids are nonlinear. In such nonlinear systems principal regions of dynamical instability can result from the effect of the periodic excitation of the fluctuated fluid flow. Evaluating the boundary frequencies for these types of instabilities had been carried out by many analytical and numerical methods. In this paper, an approximate "closed-form" solution for evaluating the principal boundary regions of instability for conservative pipes conveying pulsated fluid has been attempted. Bolotin's method was employed to split the boundaries from the stable regions. The resulting coupled-ordinary differential equations is decoupled by neglecting the effect of the mass ratio term and solved analytically. After imposing the specified boundary conditions, then the simplified formulas or transcendental equations were obtained for the pipes under consideration. These equations can give the principal boundary regions in term of the system parameters by simple calculations. The present solution was carefully checked with the "exact" solution where the mass ratio was included. The results showed good agreement for pinned-pinned clamped-pinned and clamped-clamped pipes conveying pulsating fluid. [ABSTRACT FROM AUTHOR]

In February 1851, Léon Foucault published in the Comptes rendus his famous pendulum experiment performed at the “Observatoire de Paris”. This ended two centuries of quest for an experimental demonstration of Earth rotation. One month later, the experiment was reproduced at larger scale in the Panthéon and, as early as the summer of 1851, it was being repeated in many places across the world. The next year, Foucault invented the gyroscope to get a still more direct proof of Earth rotation. The theory relied on the masterpiece treatise of Laplace on celestial mechanics, published in 1805, which already contained the mathematical expression of the force that would be discovered by Gustave Coriolis 30 years later. The idea of a fictitious inertial force proposed by Coriolis prevailed by the end of 19th century, as it was conceptually simpler than Laplace's approach. The full theory of the Foucault pendulum, taking into account its unavoidable imperfections, was not obtained until three decades later by Kamerlingh Onnes, the future discoverer of liquid helium and superconductivity. Today, Foucault's exceptional creativity is still a source of inspiration for research and the promotion of science through experimental proofs widely available to the public. [ABSTRACT FROM AUTHOR]

An improved mathematical model to study the free vibration behavior of rotating functionally graded material beam is presented, considering non-linearity up to second order for the normal and transverse shear strains. The study is carried out considering thermal loading due to uniform temperature rise and using temperature-dependent material properties. Power law variation is assumed for through-thickness symmetric functional gradation of ceramic–metal functionally graded beam. The effects of shear deformation and rotary inertia are considered in the frame-work of Timoshenko beam theory. First, the rotating beam configuration under time-invariant centrifugal loading and thermal loading is obtained through a geometrically non-linear analysis, employing minimum total potential energy principle. Then, the free vibration analysis of the deformed beam is performed using the tangent stiffness of the deformed beam configuration, and employing Hamilton’s principle. The Coriolis effect is considered in the free vibration problem, and the governing equations are transformed to the state-space to obtain the eigenvalue problem. The solution of the governing equations is obtained following Ritz method. The validation is performed with the available results, and also with finite element software ANSYS. The analysis is carried out for clamped-free beam and for clamped–clamped beam with immovably clamped ends. The results for the first two modes of chord-wise and flap-wise vibration in non-dimensional speed-frequency plane are presented for different functionally graded material compositions, material profile parameters, root offset parameters and operating temperatures. [ABSTRACT FROM AUTHOR]

This work presents the modelling, design, fabrication and test of the first micro Coriolis mass flow sensor fully fabricated in SU-8 by photolithography processes. The sensor consists of a channel with rectangular cross-section with inner opening of 100 μm × 100 μm and is actuated at resonance by Lorentz forces. Metal tracks for the actuation current are deposited on top of the chip. The chip has been tested over a flow range of 0–800 mg/min in the case of water and 0–650 mg/min for isopropyl alcohol (IPA) to confirm that the sensor measures true mass flow (at the maximum flow of the tested range, 0–800 μl/min for both water and IPA, it results in a pressure drop of 0.98 bar for water and 1.97 bar for IPA). [ABSTRACT FROM AUTHOR]

Turbines in wind farms are subject to complex mutual aerodynamic interactions, which in detail depend upon the characteristics of the atmospheric boundary layer. Our two objectives with this paper were to investigate the impact of directionally sheared inflow on the wake development behind a single wind turbine and to analyse the impact of the wakes on the energy yield and loading of a downstream turbine, which is exposed to partial and full wake conditions. We performed simulations with a framework based on a coupled approach of large-eddy simulation and an actuator line representation of an aeroelastic turbine model. Our results show that directionally sheared inflow leads to a non-symmetrical wake development, which transfers to distinct differences in the energy yield and loading of downstream turbines of equal lateral offsets in opposite direction. Therefore, the assumption of wakes being axisymmetrical could lead to notable deviations in the prediction of wake behaviour and their impact on downstream turbines for atmospheric inflow conditions, which include directional shear. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate a compact ready-to-use micro Coriolis mass flow meter. The full scale flow is 1 g/h (for water at a pressure drop < 1 bar). It has a zero stability of 2 mg/h and an accuracy of 0.5% reading for both liquids and gases. The temperature drift between 10 and 50 °C is below 1 mg/h/°C. The meter is robust, has standard fluidic connections and can be read out by means of a PC or laptop via USB. Its performance was tested for several common gases (hydrogen, helium, nitrogen, argon and air) and liquids (water and isopropanol). As in all Coriolis mass flow meters, the meter is also able to measure the actual density of the medium flowing through the tube. The sensitivity of the measured density is ~1 Hz.m3/kg.

The estuary of San Vicente de la Barquera (Cantabria, Spain) occupies two fluvial valleys that have incised into soft sedimentary rocks (Lower Mesozoic) and are controlled by inactive faults. These two estuary subsystems, the Escudo (main valley) and Gandarilla, share outer estuarine zones, i.e., a sandy bay and an estuary-mouth complex. The complexity of the system lies in the presence of a confining barrier formed by an aeolian dune/ beach system that is currently enclosed by a jetty, which has allowed the dune progradation over the past 50 years. Furthermore, connected to the inner inlet in the sand bay there is a flood-tidal delta, the most important morphosedimentary and dynamic unit. This unit exhibits a heart shape caused by the wide range of flows in this estuarine zone and channelizes the flows and sediments into the estuary, primarily during rising and high tides. In particular, the counter-clockwise surficial rotation due to the Coriolis effect is essential to the development of sand shoals, spill-over lobes, sand waves and megaripples. The presence of estuarine beaches into the bay is common in many Cantabrian estuaries, even culminating in small dune fields, in this case due to anthropogenic influences. This paper explains the impact on the estuary of human occupation and port management, focussing on the dynamic and sedimentary distribution of a bar-barrier estuary and the changes produced in its distal part by the construction of the two jetties in the mouth.