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Material flow in the actomyosin cortex of a cell, during cell division, has been found to be chiral in nature. It has been attributed to active chiral torques generated in the actomyosin cortex. Here, we explore the possible signature of such chirality during the growth of the intra-cellular membrane partition, which physically divides the cell into two compartments. We use standard hydrodynamic theory of active gel to predict possible chiral flow structures in the growing partition. While the flows in the growing annular-shaped membrane partition is believed to be radial, it can also develop non-zero azimuthal velocity components (rotation) due to chirality. We show that the direction of rotation (clock or anti-clockwise) will not solely be decided by the sign of the active chiral torque but also by the relative strengths of rotational viscosity and flow coupling parameter. [ABSTRACT FROM AUTHOR]

Event-Chain Monte Carlo (ECMC) methods generate continuous-time and non-reversible Markov processes, which often display significant accelerations compared to their reversible counterparts. However, their generalization to any system may appear less straightforward. In this work, our aim is to distinctly define the essential symmetries that such ECMC algorithms must adhere to, differentiating between necessary and sufficient conditions. This exploration intends to delineate the balance between requirements that could be overly limiting in broad applications and those that are fundamentally essential. To do so, we build on the recent analytical description of such methods as generating piecewise deterministic Markov processes. Therefore, starting with translational flows, we establish the necessary rotational invariance of the probability flows, along with determining the minimum event rate. This rate is identified with the corresponding infinitesimal Metropolis rejection rate. Obeying such conditions ensures the correct invariance for any ECMC scheme. Subsequently, we extend these findings to encompass schemes involving deterministic flows that are more general than mere translational ones. Specifically, we define two classes of interest of general flows: the ideal and uniform-ideal ones. They, respectively, suppress or reduce the event rates. From there, we implement a comprehensive non-reversible sampling of a system of hard dimers by introducing rotational flows, which are uniform-ideal. This implementation results in a speed-up of up to ∼3 compared to the state-of-the-art ECMC/Metropolis hybrid scheme. [ABSTRACT FROM AUTHOR]

The current research aims to analyse the effect of the number and shape of the blades and the curvature of the flume bottom on the performance curves of undershot water wheels, based on experimental tests conducted in a fully instrumented laboratory facility. Six wheels are tested: four wheels with plane blades (16, 24, 36, 48) and two with 24 curved blades for two flume bottom configurations. Torque, mechanical power and mechanical efficiency performance curves are determined for several rotational speed and flow rate values. Results demonstrate that the maximum efficiency is achieved for the 36-plane blade wheel, the curved flume bottom reduces water losses under the wheel and increases efficiency, and the blades’ shape strongly influences the wheel efficiency. Non-dimensional performance curves are provided to generalise the results. This research provides relevant contributions towards the development of a low-cost energy recovery solution to be applied in water infrastructures. [ABSTRACT FROM AUTHOR]

This study theoretically predicted the response of superimposed squeeze and rotational flows (SSRF) of fluids with different viscous behaviors (i.e., Newtonian, shear-thinning, and shear-thickening fluids). The theoretical predictions were verified using the plate-plate geometry for the SSRF measurements with the Newtonian and power-law fluids. In all the cases, the squeeze force increased as the gap decreased, but the response was very different for each rheological behavior. The variation in the squeeze force with the gap was not affected by the superimposed rotational shear stress value, owing to the nondependency of the viscosity on the shear for Newtonian fluids. However, for the power-law fluids, the squeeze force variation with the gap value was based on the value of the superimposed shear stress value. The decrease and increase in the viscosity with the shear stress for the shear-thinning and shear-thickening fluids, respectively, resulted in opposite trends of the squeeze force with the gap value variation. For the shear-thinning fluids, the squeeze force for each gap value decreased with increasing superimposed rotational shear stress. The opposite trend was observed for the shear-thickening fluid. In the absence of wall slip, the theoretical predictions well agreed with the experimental results. [ABSTRACT FROM AUTHOR]

The performance of three centrifugal pumps designed to operate at a rotational speed of 151.84 rad/s and flow rates of 1, 25, and 45 kg/s is being investigated for both water and non-Newtonian fluids at various rotational speeds and flow rates. The analyses are being conducted experimentally and numerically within the flow rate range of 0.25–55 kg/s and rotational speed values between 52.36 and 151.84 rad/s. Additionally, artificial neural networks (ANN) trained using experimental pump performance data are being tested with experimental and numerical values obtained at a new rotational speed of 130.9 rad/s. The non-Newtonian fluids being tested include CMC 0.2% and CMC 0.4%, comprising carboxy methyl cellulose (CMC) solution and water. The results indicate that the pump's performance when handling non-Newtonian fluids is significantly influenced by the pump's geometry, rotational speed, and flow rate. In design parameters, the head obtained with 0.2% CMC for pump 1 is 3.3% greater than that in water. For pump 2, the highest head is in water according to design parameters. Pump 3 exhibits the highest head at a CMC of 0.4 in design parameters, and this value is 0.81% higher than the value with water. Experimental and numerical results demonstrate good agreement, especially in design parameters. The head obtained from numerical analyses with the RNG k–ε turbulence model for pumps 1, 2, and 3 at design parameters is 3, 10, and 9.83 m, respectively. The corresponding experimental heads are 3, 10, and 9.84 m, respectively. However, discrepancies between these results increase with higher flow rates and the use of non-Newtonian fluids. The compatibility of ANN results with experimental results is better than with numerical results, particularly at higher flow rates than the design condition. Pump performance values estimated by ANNs are 2% lower than the experimental results. This study provides comprehensive experimental data on the use of non-Newtonian fluids in different centrifugal pumps, and it also offers important guidance for future research by comparing ANN and computational fluid dynamics. [ABSTRACT FROM AUTHOR]

This study explores how future SST warming in remote ocean basins may affect the western North Pacific (WNP) wet season climate by applying a high-resolution atmospheric general circulation model to conduct a series of numerical experiments. A marked precipitation and tropical cyclone (TC) activity reduction, as well as enhanced anticyclonic circulation, in the WNP is projected in AMIP experiments forced by SST change in a future warming scenario. The sensitivity experiments reveal that various SST warming phenomena (e.g., in the global SST warming pattern, the tropical ocean belt, the Indian Ocean, the tropical Atlantic, and the subtropical northeast Pacific) and the increase in greenhouse gas concentration could weaken the precipitation, TC activity, and circulation. By contrast, the SST warming in the WNP and eastern equatorial Pacific has opposite and mixed effects, respectively, and tends to weakly offset the dominant influences of remote ocean warming. These results indicate that the WNP, being the epicenter of the global teleconnection of divergent and rotational flow, is susceptible to the influence of the SST warming in remote ocean basins. The remote forcing as projected in future scenarios would overwhelm the enhancing effect of local SST warming and weaken the circulation, convection, and TC activity in the WNP. These findings further the understanding of how the decreased precipitation and enhanced subtropical high in the WNP may be easily triggered by remote SST warming as revealed in the AMIP-type simulations. How this effect would be affected by air–sea coupling needs further investigation. [ABSTRACT FROM AUTHOR]

This research paper presents a comprehensive study on the intricate interplay of rotational, magnetic field and heat transfer effects in squeezing fluid flow, utilizing the foundational framework of Navier–Stokes equations. Fluid flow in confined geometries has significant applications in various industrial processes, including lubrication systems, microfluidics, and heat exchangers. The integration of rotational motion, magnetic fields, and heat transfer phenomena into this context holds immense potential for optimizing performance and efficiency. The study commences with the derivation and analysis of the coupled Navier–Stokes equations, incorporating the Coriolis force due to rotational motion, the Lorentz force arising from magnetic fields, and the energy equation for heat transfer. This comprehensive model accounts for the complex interactions between these physical phenomena, offering a holistic perspective on squeezing fluid flow dynamics. Numerical analysis are conducted to investigate the behavior of fluids under the influence of rotational, magnetic field, and heat transfer effects. The results reveal intricate flow patterns, including vortex formation and heat transfer enhancement. Furthermore, the impact of key parameters such as rotational speed, magnetic field strength, and temperature gradients on flow characteristics is systematically analyzed. The Dufour effect pertains to the transfer of energy resulting from a gradient in mass concentration, occurring as a correlated consequence of irreversible processes. It functions as the inverse of the Soret effect. The temperature changes due to the concentration gradient, amplifying as the Dufour number increases. The most significant temperature rise is observed at the midpoint of the fluid domain. Conversely, the Soret number behaves in a similar but opposite manner. Tables 4–10 has been created to offer a comprehensive analysis of the optimal alignment between Homotopy Analysis Method (HAM) and BVP4c. Specifically, it demonstrates a continuous decrease in skin friction for ξ S o , ξ R d , and ξ R 2 , while showing an increase for ξ S c , ξ D o , and ξ R e m . Meanwhile, the skin friction remains constant for ξ P r . The research centers on analyzing heat and mass transfer properties within an incompressible fluid confined between two rotating and stretching disks amidst an unpredictable flow pattern. The study employs a blend of analytical and numerical approaches to solve the governing equations, delving into the intricate fluid dynamics and the intricate processes of heat and mass transfer within this intricate system. [ABSTRACT FROM AUTHOR]

Fused filament fabrication (FFF) is a widely used processing method; however, heat transfer limitations within a conventional nozzle result in relatively low flow rates, leading to lengthy production times, compared to traditional processing methods, ultimately restricting its industrial application. Recently, a novel rotational nozzle FFF three-dimensional (3 D) printer has been patented and developed to enhance processing efficiency. Despite this achievement, the fundamental mechanisms behind this novel process remain unclear. In this study, both analytical analysis and numerical simulations were conducted based on a force-controlled scaled-down experimental setup. This setup, designed according to the pressure-induced melt removal theory, provided melt throughput data under varying heater temperatures, extrusion forces, and rotational speeds. Agreement between the modeling and experimental results confirms the generalizability of the models. Modeling predictions of temperature and velocity distributions indicate that viscous dissipation affects the average temperature and filament velocity. To simulate the real-world working conditions of FFF 3 D printing, a velocity-controlled simulation was introduced. It was observed that the average melt film thickness increases with nozzle rotational speed due to viscous dissipation. Additionally, the extrusion force required for the same printing speed decreases with increasing nozzle rotational speed, primarily due to the higher shear rate reducing melt viscosity. [ABSTRACT FROM AUTHOR]

Penn State University is developing a pediatric total artificial heart (TAH) as a bridge-to-transplant device that supports infants and small children with single ventricle anomalies or biventricular heart failure to address high waitlist mortality rates for pediatric patients with severe congenital heart disease (CHD). Two issues with mechanical circulatory support devices are thrombus formation and thromboembolic events. This in vitro study characterizes flow within Penn State's pediatric total artificial heart under physiological operating conditions. Particle image velocimetry (PIV) is used to quantify flow within the pump and to calculate wall shear rates (WSRs) along the internal pump surface to identify potential thrombogenic regions. Results show that the diastolic inflow jets produce sufficient wall shear rates to reduce thrombus deposition potential along the inlet side of the left and right pumps. The inlet jet transitions to rotational flow, which promotes wall washing along the apex of the pumps, prevents flow stasis, and aligns flow with the outlet valve prior to systolic ejection. However, inconsistent high wall shear rates near the pump apex cause increased thrombogenic potential. Strong systolic outflow jets produce high wall shear rates near the outlet valve to reduce thrombus deposition risk. The right pump, which has a modified outlet port angle to improve anatomical fit, produces lower wall shear rates and higher thrombus susceptibility potential (TSP) compared to the left pump. In summary, this study provides a fluid dynamic understanding of a new pediatric total artificial heart and indicates thrombus susceptibility is primarily confined to the apex, consistent with similar pulsatile heart pumps. [ABSTRACT FROM AUTHOR]

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In this study, we evaluated the nonlinear dynamics of convection flow using the thermodynamic variational principle, focusing on scenarios where multiple external forces, such as a thermal gradient and rotational field, are applied to a shallow annular pool. We observed that with the increase in the thermal gradient, the flow changed from an axial flow to a rotational oscillatory flow with the wave amplitudes aligned. Further increasing the temperature difference led to a rotational oscillatory flow characterized by alternating wave generation and annihilation. Our analysis of the flow, considering heat fluxes orthogonal to the thermal gradient, allowed us to describe the flow state as a phase at equilibrium. The state transition of the flow was accompanied by a discontinuous jump in the heat flux, which occurred at the intersection of the entropy production curves. The first transition occurred at a temperature difference Δ T = 12.4   K   M a r a n g o n i   n u m b e r , M a = 1716 and the second at ΔT = 16.3 K M a = 2255 . Analysis based on entropy production could accurately predict the observed transition points. [ABSTRACT FROM AUTHOR]

The development of self-compacting lightweight concretes is associated with solving two conflicting tasks: achieving a structure with both high flowability and homogeneity. This study aimed to identify the technological and rheological characteristics of the flow of concrete mixtures D1400...D1600 based on hollow microspheres in comparison with heavy fine-grained D2200 concrete and to establish their structural and physico-mechanical characteristics. The study of the concrete mixtures was carried out using the slump flow test and the rotational viscometry method. The physical and mechanical properties were studied using standard methods for determining average density and flexural and compressive strength. According to the results of the research conducted, differences in the flow behaviors of concrete mixtures on dense and hollow aggregates were found. Lightweight concretes on hollow microspheres exhibited better mobility than heavy concretes. It was shown that the self-compacting coefficients of the lightweight D1400...D1600 concrete mixtures were comparable with that of the heavy D2200 concrete. The rheological curves described by the Ostwald–de Waele equation showed a dilatant flow behavior of the D1400 concrete mixtures, regardless of the ratio of quartz powder to fractionated sand. For D1500 and D1600, the dilatant flow behavior changed to pseudoplastic, with a ratio of quartz powder to fractional sand of 25/75. The studied compositions of lightweight concrete can be described as homogeneous at any ratio of quartz powder to fractional sand. It was shown that concrete mixtures with a pronounced dilatant flow character had higher resistance to segregation. The value of the ratio of quartz powder to fractional sand had a statistically insignificant effect on the average density of the studied concretes. However, the flexural and compressive strengths varied significantly more in heavy concretes (up to 38%) than in lightweight concretes (up to 18%) when this factor was varied. The specific strength of lightweight and heavy concrete compositions with a ratio of quartz powder to fractional sand of 0/100 had close values in the range of 20.4...22.9 MPa, and increasing the share of quartz powder increased the difference between compositions of different densities. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions The left atrial assist device (LAAD) is a novel continuous‐flow pump designed to treat patients with heart failure with preserved ejection fraction, a growing type of heart failure, but with limited device‐treatment options. The LAAD is implanted in the mitral plane and pumps blood from the left atrium into the left ventricle. The purpose of this study was to refine the initial design of the LAAD, using results from computational fluid dynamics (CFD) analyses to inform changes that could improve hydraulic performance and flow patterns within the LAAD.The initial design and three variations were simulated, exploring changes to the primary impeller blades, the housing shape, and the number, size, and curvature of the diffuser vanes. Several pump rotational speeds and flow rates spanning the intended range of use were modeled.Guided by the insight gained from each design iteration, the final design incorporated impeller blades with improved alignment relative to the incoming flow and wider, more curved diffuser vanes that better aligned with the approaching flow from the volute. These design adjustments reduced flow separation within the impeller and diffuser regions. In vitro testing confirmed the CFD predicted improvement in the hydraulic performance of the revised LAAD flow path design.The CFD results from this study provided insight into the key pump design‐related parameters that can be adjusted to improve the LAAD's hydraulic performance and internal flow patterns. This work also provided a foundation for future studies assessing the LAAD's biocompatibility under clinical conditions. [ABSTRACT FROM AUTHOR]

In this article, the role of slip-dependent (SD) zeta potential in the hydrodynamic characteristics of mixed electromagnetohydrodynamic (EMHD) and electroosmotic driven flow of couple stress fluid within a rotating microfluidic channel is theoretically investigated. This work is the first to analyze the hydrodynamic characteristics of slip-independent (SI) and slip-dependent (SD) zeta potentials in a rotating microchannel including a detailed analysis of Ekmann spirals in the microchannel. Ekmann spirals show the effect of rotational flow caused by different parameters, particularly, the slip parameter and the Hartmann number being the most significant ones. Ekmann plot variations, observed under both SI and SD model cases, show a significant effect on rotating flow dynamics. The effect of pertinent parameters on the rotational flow velocity, centerline velocity, and volumetric flow rate is graphically depicted. The findings of this research reveal that the SD zeta potential plays a crucial role in determining the rotating flow velocity and volume flow transport. The normalized transverse centerline in the magnitude flow velocity increases with the couple stress parameter and decreases with the slip parameter for both SI and SD model cases. Notably, the magnitude of the normalized transverse flow rate increases with rotational parameter values. In contrast, it decreases with an increase in the slip parameter under the SD model case. The outcomes of this study can be directly used in applications like transportation of biofluid models in Lab-On-a-Chip (LOC) devices and microfluidic systems under certain conditions. [ABSTRACT FROM AUTHOR]

In this paper, a parabolic trough solar collector with variable heat flux depending on various twisted tapes as a swirl generator with cerium oxide, copper oxide, and multi-walled carbon nanotubes nanofluids with different volume fractions is presented. First, the impact of different twisted tapes is discussed, and the next part analyzes the influence of different volume fractions of nanofluids on improving the outlet temperature and the heat transfer coefficient. Finally, the best volume fraction of these nanofluids is used to form the hybrid nanofluid, and its effect on the turbulence thermal efficiency is numerically assessed. The obtained outcomes indicate that using a quadruple twisted tape improves the rate of heat transfer because it induces more rotational flow compared to other cases. Moreover, hybrid nanofluids of cerium oxide/copper oxide with a 2% volume fraction demonstrated the most increased thermal efficiency. Furthermore, to facilitate a broader utilization of the results, a precise relationship for the pressure drop and heat transfer coefficient in relation to alterations in terms of geometry, fluid velocity, and thermophysical properties obtained through statistical analysis is provided. Additionally, the assessed parabolic trough solar collector and a water heater with a capacity of 18,000 kcal/h were compared to evaluate the reduction in greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

This paper explores the combined influence of an axial electric field and a perpendicular magnetic field imposed on rotating micro-parallel plates immersed in an electrolyte solution. A specialized computer program was developed to solve the velocity as well as the EDL potential fields using the finite difference method, employing the Debye-Hückel (DH) approximation to linearization the EDL potential. The study examines the influence of various non-dimensional parameters, including rotational speed (ω), Hartmann number (Ha), Debye-Hückel parameter (κ), and the non-dimensional parameter ' S', on axial, and transverse velocities, wall shear stress, and net flow rate. Results demonstrate that, both velocity components decrease with increased rotational speed and Hartmann number, while the net flow rate increases with the Debye-Hückel parameter for both rotating and non-rotating systems. The impact of these parameters on shear stress was also analyzed. Analysis of Ekmann spirals in the velocity plane revealed closed spirals at a higher rotational speed and open spirals at lower speeds, with spiral size reducing as rotational speed increases. [ABSTRACT FROM AUTHOR]

The Tea Leaf Paradox (TLP) describes unsteady fluid motions which help entrain and deposit suspended particles at the center of rotation. Various applications depend on the TLP for particle separations—spanning orders of magnitude in length scales—making it an important problem in fluid mechanics. Despite papers describing the phenomenon, the efficacy of particle separation using the TLP remains unclear as to the relative importance of, for example, hydrostatics, particle-fluid density ratio, wall friction, liquid bath aspect ratio and the rotation speed. The dynamics involved are notably complex and require a careful tuning of each variable. In this study, we have investigated the role of the limit of the aggregation dynamics in rotational flows within 3D-printed vessels of various sizes in tandem with particle imaging to probe the dissipation effects on the particle motions. We have found that the liquid bath aspect ratio limits how much aggregation may occur for a particle-fluid density ratio greater than unity (e.g., ρ p / ρ f > 1 ), where ρ p is the density of the particle and ρ f is the ambient fluid density. [ABSTRACT FROM AUTHOR]

The Tea Leaf Paradox (TLP) describes unsteady fluid motions which help entrain and deposit suspended particles at the center of rotation. Various applications depend on the TLP for particle separations—spanning orders of magnitude in length scales—making it an important problem in fluid mechanics. Despite papers describing the phenomenon, the efficacy of particle separation using the TLP remains unclear as to the relative importance of, for example, hydrostatics, particle-fluid density ratio, wall friction, liquid bath aspect ratio and the rotation speed. The dynamics involved are notably complex and require a careful tuning of each variable. In this study, we have investigated the role of the limit of the aggregation dynamics in rotational flows within 3D-printed vessels of various sizes in tandem with particle imaging to probe the dissipation effects on the particle motions. We have found that the liquid bath aspect ratio limits how much aggregation may occur for a particle-fluid density ratio greater than unity (e.g., ρp/ρf>1), where ρp is the density of the particle and ρf is the ambient fluid density.

Weird horizontal shapes of branches, in large branching estuaries, often cause significant flood risks and environment-related problems. People usually resort to engineering methods to improve the horizontal shape of the weird branches and solve related issues. The responses of the riverbed evolution of a branching estuary to anthropogenic activity are complicated because of complex estuarine hydrodynamics and sediment transports, especially when the project locates specially (e.g., at estuary outlets). The North Branch of the Yangtze Estuary has a narrow upper reach which is almost orthogonal to the South Branch and has a trumpet-shaped lower reach with a wide outlet. The weird horizontal shape of the North Branch brings significant flood risks to cities along this branch, the shrinkage of its entrance, and other problems. In this study, a regulation of the North Branch, which is launched at Guyuan Sand (GYS) just outside the exit of the North Branch, is taken as an example. The GYS regulation aims to improve the weird horizontal shape of the North Branch by building new layouts of outlets, by which people decrease the flood risk of the surrounding cities. The GYS regulation is studied using a 2D numerical model. The riverbed evolution of the Yangtze Estuary in a typical hydrological year is simulated, while the water/sediment fluxes at cross-sections of branches in the estuary during a spring/neap tide are quantitatively calculated. It is found that the regulation changes the rotational flows near the shore, and further reshapes the estuarine circulations of mass inside the outlets, especially exchanges of water/sediment between different branches. The regulation directly changes the riverbed evolution at the outlet of the North Branch, and meanwhile has significant indirect influences on the riverbed evolution of the entrance of the North Branch. The varying riverbed evolution at the entrance of the North Branch and the varying water/sediment fluxes, under different designs of regulations, are related and analyzed. An essential improvement for the weird horizontal shape of the North Branch by an engineering method is shown to be possible, while the regulation mechanism of the engineering method and the response of estuarine riverbed evolution to the regulation are clarified. This study provides a new insight for improving estuarine branches with weird horizontal shapes, by reshaping the tidal processes and the accompanying sediment transports in a branching estuary. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethanes (TPU) have attracted increasing attention due to their excellent flexibility, chemical stability, processability and greenness. The traditional processes generally limit them to civil and industrial applications, but electrospun TPU nanofibers with high porosity, high specific surface area and superior mechanical properties are promising in emerging fields. TPU nanofibers' properties are affected by various electrospinning parameters, such as solution concentration, applied voltage, flow rate and rotational speed. Thus, 29 sets of experiments were designed here by the efficient and low-cost response surface methodology (RSM). The analysis of variance (ANOVA) revealed that the model agrees well with experimental results, and solution concentration is the most crucial parameter affecting nanofibers' morphology and diameter. Based on it, the impacts of solution concentration and orientation on the mechanical properties of the TPU nanofiber membrane were investigated. Benefiting from the stress transfer and network deformation, the TPU nanofiber membranes parallel to the collection direction possessed the highest stress strength (23.71 MPa), while the nanofiber membranes vertical showed the widest strain range (485%). This study provides useful guidance for the preparation of high-performance TPU nanofibers, contributing to expanding its applicability in emerging fields such as biomedical, filtration and separation, and flexible sensing. [ABSTRACT FROM AUTHOR]

Enhanced momentum and heat transport in a three-dimensional rotating disk boundary layer due to the consideration of a wavy disk surface is an already known fact in the literature. Such a transport enhancement is primarily associated with two fundamental attributes of the wavy disk: the increased surface area and the enhanced convection due to the surface undulations. However, there exists no further information about their individual role, mutual interaction, and individual share in enhancing the convective transport in the rotating disk boundary layer. This study aims to investigate these facts in detail by considering radially heterogeneous different wavy configurations on the disk surface. It is revealed that the said attributes contribute non-trivially to enhance the transport phenomena. Their impactful role is identified due to the strengths of circumferential and crossflow velocity components, the magnitude of flow swirl angle, and hence due to the coefficients of skin friction and their inter relationship. In this regard, a fundamental benchmark regarding the relative strength of the two coefficients of skin friction is identified from the flat disk case. Decisive observations regarding the impact of surface undulations and the increased surface area of the wavy disk on the enhanced convective transport are made with the aid of this benchmark. It is observed that the enhanced transport phenomena, especially the heat transfer, mainly depend upon the further dominance of the circumferential velocity component. In the situations of increased dominance of rotational flow K w > K f , the increased convection and surface area collectively contribute to enhance the thermal transport while in a reverse situation K w < K f the convection contributes adversely by even reducing the impact of the increased surface area. In the neutral situation where the dominance of rotational velocity is neither increased nor decreased (i.e., K w ≈ K f ), any increase in the transport phenomena is wholly due to the increased surface area. Therefore, the presence of surface undulations or increase in surface area is not the only criterion for an optimum rise in the transport phenomena, rather the impact of surface undulations on the velocity profiles is important which is manipulated due to their positioning on the disk surface. It is observed that the presence of surface undulations in the central and intermediate regions on the disk surface causes to increase the gradients of the crossflow velocity while their presence in the near rim location causes to enhance the gradients of the circumferential velocity. Thus, the configurations that have higher undulations in the near rim region outperform the other configurations. [ABSTRACT FROM AUTHOR]

By considering the rotationality of shear flow, we distinguish between tube segments created by reptation before the inception of shear flow and those created during flow. Tube segments created before inception of shear flow experience both stretch and orientation, while tube segments created after inception of flow are not stretched, but are only aligned in the flow direction. Based on this idea, the Rotation Zero Stretch (RZS) model allows for a quantitative description of the start-up of shear flow and stress relaxation after step-shear strain experiments, in agreement with data of polystyrene long/short blends and corresponding polystyrene 3-arm star polymers investigated by Liu et al. (Polymer 2023, 281:126125), as well as the shear viscosity data of poly(propylene carbonate) melts reported by Yang et al. (Nihon Reoroji Gakkaishi 2022, 50:127–135). In the limit of steady-state shear flow, the RZS model converges to the Doi-Edwards IA model, which quantitatively describes the steady-state shear viscosity of linear polymer melts and long/short blends. The assumption of "non-stretching" of tube segments created during rotational flow is therefore in agreement with the available experimental evidence. Three-arm star polymers behave in a similar way as corresponding blends of long and short polymers confirming the solution effect of the short arm in asymmetric stars. The analysis of step-shear strain experiments reveals that stress relaxation is at first dominated by stretch relaxation, followed at times larger than the Rouse stretch relaxation time by relaxation of orientation as described by the damping function of the Doi-Edwards IA model. The RZS model does not require any nonlinear-viscoelastic parameter, but relies solely on the linear-viscoelastic relaxation modulus and the Rouse stretch relaxation time. [ABSTRACT FROM AUTHOR]

Objectives: Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has been associated with poor outcomes. Meanwhile, the fluid dynamic and biomechanical characteristics associated with partial thrombosis remain to be elucidated. This retrospective, single-center study tested the association between FL fluid dynamics and biomechanics and the presence and extent of FL thrombus. Methods: Patients with chronic non-thrombosed or partially thrombosed FLs in the descending aorta after an aortic dissection underwent computed tomography angiography, cardiovascular magnetic resonance (CMR) angiography, and a 4D flow CMR study. A comprehensive quantitative analysis was performed to test the association between FL thrombus presence and extent (percentage of FL with thrombus) and FL anatomy (diameter, entry tear location and size), fluid dynamics (inflow, rotational flow, wall shear stress, kinetic energy, and flow acceleration and stasis), and biomechanics (pulse wave velocity). Results: Sixty-eight patients were included. In multivariate logistic regression FL kinetic energy (p = 0.038) discriminated the 33 patients with partial FL thrombosis from the 35 patients with no thrombosis. Similarly, in separated multivariate linear correlations kinetic energy (p = 0.006) and FL inflow (p = 0.002) were independently related to the extent of the thrombus. FL vortexes, flow acceleration and stasis, wall shear stress, and pulse wave velocity showed limited associations with thrombus presence and extent. Conclusion: In patients with chronic descending aorta dissection, false lumen kinetic energy is related to the presence and extent of false lumen thrombus. Clinical relevance statement: In patients with chronic aortic dissection of the descending aorta, false lumen hemodynamic parameters are closely linked with the presence and extent of false lumen thrombosis, and these non-invasive measures might be important in patient management. Key Points: • Partial false lumen thrombosis has been associated with aortic growth in patients with chronic descending aortic dissection; therefore, the identification of prothrombotic flow conditions is desirable. • The presence of partial false lumen thrombosis as well as its extent was related with false lumen kinetic energy. • The assessment of false lumen hemodynamics may be important in the management of patients with chronic aortic dissection of the descending aorta. [ABSTRACT FROM AUTHOR]

Three-dimensional mathematical model was established to investigate the solidification behavior during the continuous casting of a round bloom with the diameter of 0.7 m, where a novel swirling flow submerged entry nozzle (SEN) combined with mold electromagnetic stirring (M-EMS) method was used. The results show that an impinging flow phenomenon, which was normally formed in conventional single-port SEN casting, was effectively eliminated by adopting the new method. Molten steel from the swirling flow SEN port uniformly moved to the solidification front, which improved the dissipation rate of molten steel super-heat. When the rotational direction of the swirling flow in SEN was in the same direction as M-EMS, the super-heat of molten steel in mold can be decreased by 5 K, compared to the use of a conventional SEN with M-EMS. As the current intensity decreased from 310 to 100 A, the super-heat of molten steel in the mold center region was reduced by 3 K. This is due to that the shielding effect of M-EMS on rotational flow momentum from the swirling flow SEN became weak as the stirring intensity decreased. In addition, molten steel temperature near the meniscus under the current intensity of 310 and 100 A was 1787 K and 1790 K, respectively. The solidified shell thickness obtained by using 100 A current intensity was about 1 × 10−3 m larger than that of 310 A current intensity. [ABSTRACT FROM AUTHOR]

Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurements of nitric oxide (NO) using a Quantum Cascade Laser (QCL) in the vicinity of 5.26 μm were conducted in a hypervelocity flow generated in the Texas A&M Hypervelocity Expansion Tunnel (HXT). The nascent NO was produced downstream of symmetric Mach reflections generated in Mach 8.5 flows with stagnation enthalpies from 6.9 to 11.1 MJ/kg. Path-averaged flow parameters of rotational and vibrational temperatures and NO concentration at a measurement rate of 30 kHz were obtained. By probing the R-branch of the fundamental absorption band in NO, thermal nonequilibrium and NO concentration levels in the post-shock region were measured. Measurements are compared to equilibrium calculations. NO equilibrium values during the 1 ms test period differ from the experimental rotational and vibrational measurements across the same time period. The experimental measurements of the rotational temperature show a consistent value around 3000 K larger than the recovered vibrational temperature across any run. The NO concentrations in all runs are near to the reported equilibrium value; often beginning higher than, and over time decaying to, the equilibrium concentration value of the specific tunnel run. [ABSTRACT FROM AUTHOR]

We consider plane, steady, homogeneous, rotational shearing flows of a granular gas of identical, inelastic, frictionless spheres. We introduce the balance equation for the second moment of the particle velocity fluctuations, solve it in an approximate way for shearing flows with arbitrary amounts of rotation, and determine the stress tensor based on these solutions. We consider the stress determined in this way in the context of Material Frame Indifference. [ABSTRACT FROM AUTHOR]

We derive a new quasilinear nonlocal shallow water equation of Camassa-Holm type with higher-order nonlinearities from the governing equations for large-amplitude gravity water waves, which incorporates an ambient underlying linear shear flow and can be recognized as the higher-order generalization of the compressible hyper-elastic rod model in the material science. The mathematical modeling is implemented for the rotational water flow in the general form compared with the known models. Moreover, the local well-posedness in Besov spaces of the corresponding Cauchy problem is studied. [ABSTRACT FROM AUTHOR]

A variable-speed pump-turbine is the core component of a hydraulic storage and energy generation station. When the pump-turbine operates at a constant speed, its response to the power grid frequency is poor. In order to improve the hydraulic efficiency of the pumped storage unit, variable-speed units are used. However, there has been no numerical study on the effect of the rotational flow characteristics within the gap of a variable-speed pump-turbine. This paper calculates the flow characteristics within the gap of a variable-speed pump-turbine under three typical pump modes (maximum head minimum flow condition, minimum head maximum flow condition, and maximum speed condition). The research results indicate that the rotational speed significantly affects the pressure distribution, velocity distribution, and turbulent kinetic energy distribution within the crown and band gaps. The higher the speed, the larger the area of the high-pressure region before the runner inlet compared to other operating conditions, and similarly, the low-pressure area after the runner outlet is also larger than in other operating conditions. The change in speed mainly affects the internal flow field of the crown gap, with the most noticeable changes occurring in the pressure and flow velocity at the inlet and outlet of the crown gap. There is a clear trend of pressure drop and velocity increase within the gap as the speed increases. However, with the increase in speed, the pressure distribution and flow velocity within the band gap remain almost the same. In addition to speed changes, it is observed that the pressure within the gap and the flow velocity within the passages are also related to the head, especially in the condition of maximum head, where this relationship becomes more noticeable. [ABSTRACT FROM AUTHOR]

Constraining the processes that drive coronal heating from observations is a difficult task due to the complexity of the solar atmosphere. As upcoming missions such as the Multi-slit Solar Explorer (MUSE) will provide coronal observations with unprecedented spatial and temporal resolution, numerical simulations are becoming increasingly realistic. Despite the availability of synthetic observations from numerical models, line-of-sight effects and the complexity of the magnetic topology in a realistic set-up still complicate the prediction of signatures for specific heating processes. 3D magnetohydrodynamic (MHD) simulations have shown that a significant part of the Poynting flux injected into the solar atmosphere is carried by small-scale motions, such as vortices driven by rotational flows inside intergranular lanes. MHD waves excited by these vortices have been suggested to play an important role in the energy transfer between different atmospheric layers. Using synthetic spectroscopic data generated from a coronal loop model incorporating realistic driving by magnetoconvection, we study whether signatures of energy transport by vortices and eventual dissipation can be identified with future missions such as MUSE. [ABSTRACT FROM AUTHOR]

'This research aims to look at the consequences of diffusion thermo, Hall, ion slip, and radiation absorption on the unsteady MHD turbulent rotational flow of second-grade fluid through porous materials while also regarding the outcomes of the chemical retort and heat absorption. When the ratio between the number of collisions between fluid electrons in a cyclotron and the number of collisions between electrons and atoms is large, Hall effects (the Hall parameter) become important. The regular perturbation approach investigates the outlines of velocity segments, temperature dispersion, and concentration. The statistics for shear stress, the Nusselt numeral, and the Sherwood factor are written down on the panel. Graphs show how changes in different physical parameters cause changes in a fluid's speed, temperature, and concentration patterns. In the end, it can be said that the primary and secondary velocities speed up significantly as the Hall and ion-slip parameters get bigger. This effect was also seen in the shearing stress's axial and transverse components. The increasing importance of the thermal diffusion parameter increases both the initial and secondary velocities'. [ABSTRACT FROM AUTHOR]

This work inspects 3D magnetohydrodynamic hybrid nanofluid flow on a permeable elongating surface. The emphasis of this paper is on the study of hybrid nanofluid flow within a rotating frame, taking into account the simultaneous impact of both thermal and velocity slip boundary conditions. The chosen base fluid is water, and the hybrid nanofluid comprises two nanoparticles Cu\text{Cu} and Al2O3{\text{Al}}_{2}{\text{O}}_{3}. The effect of the magnetic and porosity parameters is taken into account in the momentum equation. The thermal radiation, Joule heating, and heat source are considered in the energy equation. Using a similarity system, we transform the PDEs of the proposed model into ODEs, which are then solved numerically by the bvp4c technique. The magnetic field shows a dual nature on primary and secondary velocities. Enrich magnetic field decreases the primary velocity and enhances the secondary velocity. The rotation parameter has an inverse relation with both velocities. The temperature profile amplified with the escalation in heat source, magnetic field, rotation factor, and Eckert numbers. The skin friction is boosted with magnetic parameters while the Nusselt number drops.

A class of exact solutions to the Navier–Stokes equations for an axisymmetric rotational incompressible flow is obtained. Invariant manifolds of flows that are axisymmetric about a given axis in three-dimensional coordinate space are found, and the structure of solutions is described. It is established that typical invariant regions of such flows are figures of rotation homeomorphic to the torus, which form a topological stratification structure, for example, in a ball, cylinder, and general complexes made up of such figures. The results extend to similar solutions of the system of MHD equations and Maxwell's electrodynamic equations, which have analogous properties in . Examples are given of axisymmetric vorticity vector fields and topological stratifications they generate on manifolds in that are invariant under the dynamical systems specified by these fields. [ABSTRACT FROM AUTHOR]

The main motivation behind this research work is the electroosmotic flow (EOF), which characterizes the movement of charged particles in a fluid when subjected to an external electric field, which offers precise control over fluid movement without mechanical components. The study of bio-fluids in rotating microfluidic platforms is becoming much more significant. Hence, it is important to discuss the non-Newtonian fluids in such environments. This paper analytically investigates the hydrodynamic characteristics of combined electromagnetohydrodynamic (EMHD) and EOF transport of non-Newtonian fluid through a rotating microchannel with Navier-slip boundary conditions at the walls. The couple stress fluid model is considered a non-Newtonian fluid in the flow domain. The linearized Poisson-Boltzmann equation is considered inside the electric double layer (EDL). The modified Stokes equation is governed by a combined imposed magnetic and EOF field. Closed form expressions are obtained for electrical potential, flow velocity, and volume flow rate in the channel using analytical methods. The dependence of rotating electromagnetic flow velocity and flow rates on appropriate parameters is explained. It is found that the rotational flow velocity displays an opposite pattern when the couple stress parameter and electric field intensity parameters are varied due to the influence of channel rotation. It is also found that the secondary flow rate ratio is amplified with the Hartmann number and slip length parameter, due to the stronger impact of the non-Newtonian behaviour than the Newtonian situation on the volume flow rate at a relatively higher rotational value. The findings of this study may aid in the design and analysis of practical thermal micro/nano-equipment for transporting biofluids. [ABSTRACT FROM AUTHOR]

We present a facile and versatile strategy for enabling CsPbI3 rods to self-assemble at an air-water interface. The CsPbI3 rods, which float at the air-water interface, align under the influence of the rotational flow field due to the vortex motion of a water subphase. The aligned CsPbI3 rods could be transferred onto various substrates without involving any sophisticated instrumentation. The temperature of the subphase, the concentration of the CsPbI3 aliquot, the rotational speed inducing vortex motion, and the liftoff position and angle of the substrate were optimized to achieve high coverage of the self-assembled rods of CsPbI3 on glass. The Rietveld refinement of the XRD profile confirms that the aligned CsPbI3 is in the pure orthorhombic phase ascribed to the Pnma space group. The hydrophilic carboxylic group of the oleic acid attaches to the Pb atoms of the halide perovskite rods, while their hydrophobic tails encapsulate the rods within their shell, creating a shielding barrier between the water and the perovskite surface like a reverse micelle. The aligned CsPbI3 rods exhibit a nearly 47-fold increment in current upon exposure to ammonia gas (amounting to 5.6 times higher sensitivity in ammonia sensing) compared to the nonaligned CsPbI3 rods. [ABSTRACT FROM AUTHOR]

The evolutions of small and large compressive pulses are studied in a two-phase flow of gas and dust particles with a variable azimuthal velocity. The method of relatively undistorted waves is used to study the mechanical pulses of different types in a rotational, axisymmetric dusty gas. The results obtained are compared with that of nonrotating medium. Asymptotic expansion procedure is used to discuss the nonlinear theory of geometrical acoustics. The influence of the solid particles and the rotational effect of the medium on the distortion are investigated. In a rotational flow it is observed that with the increase in the value of rotational parameter, the steepening of the pulses also increases. The presence of dust in the rotational flow delays the onset of shock formation thereby increasing the distance where the shock is formed first. The rotational and the dust parameters are observed to have the same effect on the shock strength. [ABSTRACT FROM AUTHOR]

The flow and heat transfer of a steady, viscous biomagnetic fluid containing magnetic particles caused by the swirling and stretching motion of a three-dimensional cylinder has been investigated numerically in this study. Because fluid and particle rotation are different, a magnetic field is applied in both radial and tangential directions to counteract the effects of rotational viscosity in the flow domain. Partial differential equations are used to represent the governing three-dimensional modeled equations. With the aid of customary similarity transformations, this system of partial differential equations is transformed into a set of ordinary differential equations. They are then numerically resolved utilizing a common finite differences technique that includes iterative processing and the manipulation of tridiagonal matrices. Graphs are used to depict the physical effects of imperative parameters on the swirling velocity, temperature distributions, skin friction coefficient, and the rate of heat transfer. For higher values of the ferromagnetic interaction parameter, it is discovered that the axial velocity increases, whereas temperature and tangential velocity drop. With rising levels of the ferromagnetic interaction parameter, the size of the axial skin friction coefficient and the rate of heat transfer are both accelerated. In some limited circumstances, a comparison with previously published work is also handled and found to be acceptably accurate. [ABSTRACT FROM AUTHOR]

The sea surface can be described by means of the superposition of many sinusoidal functions. However, quite often the amplitude of each component turns out to be much smaller than its wavelength, and any component evolves independently of the others. Hence, it is common to investigate the dynamics of a simple monochromatic surface wave. Hereinafter, the flow generated by a monochromatic surface wave within the bottom boundary layer over a rippled sea bed is determined by means of the numerical integration of vorticity and continuity equations. The forcing term that drives the fluid motion within the boundary layer is evaluated assuming that the steepness of the monochromatic surface wave is much smaller than one and considering the first term of the Stokes expansion. Even though the irrotational flow that forces the viscous rotational flow near the sea bottom is symmetric with respect to the ripple crests, Blondeaux and Vittori ["A route to chaos in an oscillatory flow: Feigenbaum scenario," Phys. Fluids A 3(11), 2492–2495 (1991a)] showed that the symmetry of the flow field is broken when the Reynolds number becomes larger than a threshold value R δ , t 1 that depends on the geometrical characteristics of the ripples. The results of Blondeaux and Vittori ["A route to chaos in an oscillatory flow: Feigenbaum scenario," Phys. Fluids A 3(11), 2492–2495 (1991a)] suggest that, when the Reynolds number is larger than R δ , t 1 but not too far from it, a steady current is also generated. Hereinafter, the steady velocity component is determined as a function of the ripple characteristics. [ABSTRACT FROM AUTHOR]

Highly indium-rich group-III nitrides are attracting attention for advancing our capacity to create highly effective optical emitters at extended visible/IR wavelengths or for enhancing bandgap engineering possibilities within the group-III nitride material framework. Current methods of synthesis are constrained in their efficacy, partially owing to the low decomposition temperature of indium nitride. Implementation of a new design of a vertical high-pressure spatial chemical vapor deposition (HPS-CVD) reactor with six separated precursor source zones and a rotating wafer carrier disk carrying four 2-inch wafers is proposed and analyzed using COMSOL Multiphysics as a commercial computational fluid dynamics (CFD) program to study the fluid phenomena inside the numerical domain. This study focuses on understanding the different flow patterns within the chambers at super-atmospheric conditions (5 atm to 30 atm) and identifying suitable operating conditions under which smooth and dominant vortex-free flow is achieved. Four 2-inch wafers are heated to maintain a temperature of 1200–1300 K at each pressure and gas type. Three different gas types (nitrogen, hydrogen, and ammonia) are used, and the impacts of different inlet flow velocities and rotational speeds are investigated and discussed. An operating matrix is presented for each analyzed system pressure providing suitable combinations of these operational variables for smooth flow in the chambers. Each gas type was identified to have a range of suitable rotational and inlet velocity regimes at each operating pressure. Overlap of these three gas-specific operating condition windows resulted in the identification of a generally suitable operating condition for smooth flow patterns in the system regardless of the gas type used, as required for the growth of group-III nitride materials. [ABSTRACT FROM AUTHOR]

The present work is dedicated to the study of multiphase turbulent and three-dimensional rotational flow in dust cyclones, a contribution to air pollution control. Cyclones are widely used devices for the separation of constituents from solid-gas mixtures in industry. In order to improve the filtration efficiency of cyclones, and to reduce the pressure drop, parametric numerical simulation studies using the Fluent code have been conducted to characterise the effects of the parameters affecting the operation of these devices through their performance indicators. In this work, the effect of inlet velocity and the particle size on the turbulent flow air in the cyclone is presented. Numerical simulation of the flow by Fluent code using three numerical models: the first based on the dissipation of kinetic energy by viscosity (RNG) K-epsilon and standard K-epsilon as well as the last based on the solution of Reynolds stress equations (RSM), combined with the multiphase mixing model, gave interesting results in terms of the pressure and flow field in the separator, the variation of inlet velocity, and the variation of particle size. Validation with experimental and empirical results showed the advantage of the Reynolds stress turbulence model (RSM) over the standard K-epsilon and RNG K-epsilon. The RSM model better captures physical phenomena in an intense vortex flow in the presence of walls. But it is characterised by a very long calculation time and requires large machine resources. An alternative to this model is RNG K-epsilon model, which offers a reasonable calculation time with acceptable results (maximum deviation of 5 %) for speed values below 10 m/s. In the absence of numerical resources, certain empirical models such as those of First (for the evaluation of pressure drop) and Iozia and Leith (for evaluation of efficiency) may well be useful for the dimensioning of the cyclone. [ABSTRACT FROM AUTHOR]

Rotational buoyancy assumes a substantial role in a multitude of natural and engineering systems, with particular emphasis on astrophysical and geophysical scenarios. The primary objective of this study is to delve into the intricate dynamics of a rotational flow subjected to forces from rotational buoyancy, magnetic field, Hall effects, and infrared radiation in a Casson fluid medium adjacent to a thermal plate. The LT technique is harnessed to yield the closed‐form solutions for the dimensionless governing flow system. Through graphical analyzes, the physical implications of key contextual parameters are elucidated. Our findings demonstrate that Hall currents and rotational buoyancy forces jointly act to restrict primary fluid motion while amplifying secondary motion. An upswing in the Casson parameter leads to a marked reduction in the magnitude of the velocity components. Furthermore, intensified infrared radiation results in a more flattened thermal distribution. The primary directional shear stress attenuates, while an inverse bias is observed for the shear stress along the secondary direction, particularly with higher values of the Hall and rotation parameters. The insights gained from this study have practical implications for the design and operation of various systems involving rotational components, such as rotary machinery, automotive systems, and industrial automation, and contribute to weather forecasting and climate modelling. [ABSTRACT FROM AUTHOR]

This paper is concerned with the well-posedness theory and geometric property of steady two-dimensional incompressible jet flow with vorticity and gravity. The main results show that for given incoming mass flux and atmospheric pressure at outlet, there exists a unique incompressible jet flow issuing from a semi-infinitely long nozzle, and the free boundary initiates smoothly at the separation point. Moreover, we obtain the single intersection property of the free boundary by under-over theorem. As a consequence, the monotonicity of the free boundary will be established. [ABSTRACT FROM AUTHOR]

In order to solve the problem of gap flow field divergence and poor forming accuracy in the electrochemical machining (ECM) titanium alloy inner helix, the pull reverse flow and pull downstream cathode physical models as well as the simulation models of machining gap flow field are established respectively in this paper. Different inclination angles of the liquid supply hole effected on the pull downstream cathode rotational flow field uniformity were explored. The results showed that the gap flow field distribution of the pull downstream cathode is better than pull reverse flow cathode, and the distribution of the rotational flow field formed when the inclination angle of the liquid supply hole achieves 40° is relatively uniform. Under the condition of voltage 12 V, cathode feed speed 15 mm/min, composite electrolyte 3%NaCl + 10%NaNO3 + 6%NaClO3, electrolyte temperature 30 °C, and electrolyte inlet pressure 2 MPa, the 800-mm length of titanium alloy inner helix sample was machined stably and reliably by the pull downstream cathode structure, which surface roughness is Ra0.8 μm. [ABSTRACT FROM AUTHOR]

This study investigated the kinetic and potential energy budgets during the slow (SI) and rapid intensification (RI) periods of Typhoon Mujigae, which occurred in October 2015, by conducting a Weather Research and Forecasting model simulation. We found that the kinetic energy conversion between asymmetric and symmetric rotational circulations in the lower troposphere plays a pivotal role in initiating the difference in the tendency of symmetric rotational kinetic energy between the RI and SI via the horizontal advection process of asymmetric circulations. Southerly and easterly environmental flows transported asymmetric anticyclonic flows in SI and cyclonic flows in RI to the radius of maximum wind, respectively, where asymmetric rotational circulation was developed by vertical shear of environmental flow. Such transports initiate the growth of symmetric cyclonic rotational circulation from SI to RI. The kinetic energy conversion of symmetric divergent circulations supported by symmetric potential energy accelerates the growth of symmetric rotational kinetic energy from SI to RI. These findings can shed light on the fundamental dynamics of the RI of tropical cyclones. Plain Language Summary: The rapid intensification of typhoons in the offshore areas of China often leads to severe economic losses after landfall. Accurate forecasting of rapid intensification can help improve governmental decision‐making to reduce these losses. Understanding the physical processes associated with rapid intensification is crucial to achieving this goal. In this comparative study, we analyzed modeling data from the slow and rapid intensification of Typhoon Mujigae, which occurred in 2015, to identify the key physical processes responsible for its rapid intensification. During this period, Mujigae moved northwestward from an area of southerly winds during slow intensification to an area of easterly winds during rapid intensification. Easterly winds provide favorable environmental conditions for initiating the growth of cyclonic circulation at the lower level. The conversion of potential energy into symmetric divergent kinetic energy accelerates the intensification of Mujigae through the interaction between convergence and cyclonic circulation. Key Points: The conversion between asymmetric and symmetric rotational kinetic energies determines the slow (SI) and rapid (RI) intensification of MujigaeThe radial advection of the azimuthal wavenumber‐1 rotational flow controls the conversion depending on the environmental circulationThe movement of Mujigae into an area of easterly winds accelerates the growth of symmetric rotational kinetic energy from SI to RI [ABSTRACT FROM AUTHOR]

Inelastic interactions between a small, intense dipole and a weak, neutral monopole in two-dimensional flows are analysed. The neutral vortex has vanishing exterior potential flow and the interactions involve the rotational flow of the vortices. It is shown that dipoles of small-size but large-amplitude, relative to the neutral vortex, may cross the vortex and scatter while leave the vortex stable. [ABSTRACT FROM AUTHOR]

The ability to perceive biological motion is crucial for human survival, social interactions, and communication. Over the years, researchers have studied the mechanisms and neurobiological substrates that enable this ability. In a previous study, we proposed a descriptive Bayesian simulation model to represent the dorsal pathway of the visual system, which processes motion information. The model was inspired by recent studies that questioned the impact of dynamic form cues in biological motion perception and was trained to distinguish the direction of a soccer ball from a set of complex biological motion soccer-kick stimuli. However, the model was unable to simulate the reaction times of the athletes in a credible manner, and a few subjects could not be simulated. In this current work, we implemented a novel disremembering strategy to incorporate neural adaptation at the decision-making level, which improved the model's ability to simulate the athletes' reaction times. We also introduced receptive fields to detect rotational optic flow patterns not considered in the previous model to simulate a new subject and improve the correlation between the simulation and experimental data. The findings suggest that rotational optic flow plays a critical role in the decision-making process and sheds light on how different individuals perform at different levels. The correlation analysis of human versus simulation data shows a significant, almost perfect correlation between experimental and simulated angular thresholds and slopes, respectively. The analysis also reveals a strong relation between the average reaction times of the athletes and the simulations. [ABSTRACT FROM AUTHOR]

With the help of Clebsch's potentials, we propose a Bateman–Luke-type variational principle for a boundary- value problem with a free (unknown) interface between two ideal compressible barotropic fluids (liquid and gas) admitting rotational flows. [ABSTRACT FROM AUTHOR]

This paper is concerned with the monotonicity and convexity of the incompressible rotational cavity flow past a fixed obstacle. More precisely, we first establish the single intersection property of the free boundary by the Serrin's under–over theorem, and prove the monotonicity of the free boundary with respect to the obstacle. If the obstacle is concave to the fluid, it is proved that the free boundary is convex to the fluid. [ABSTRACT FROM AUTHOR]

The article "ON THE VORTEX IDENTIFICATION WITHIN A LINEAR BLADE CASCADE - AN EXPERIMENTAL RESEARCH" discusses the identification of vortical structures within a linear blade cascade using H criteria. The study examines the impact of the inlet flow angle on the velocity field and vortical structures, as well as the effect of the H threshold on vortex identification. The article provides insights into the complex flow through a turbine and the formation of vortices in blade cascades. The second article, "VR helicity density and its application in turbomachinery tip leakage flows" by Y. Tang and Y. Liu, explores the concept of VR helicity density and its relevance in turbomachinery tip leakage flows. The authors provide a detailed analysis of the topic, discussing the theoretical background and practical applications. This article is a valuable resource for researchers and professionals in the field of turbomachinery. [Extracted from the article]

The responses of atmospheric kinetic energy (KE) spectra to three convective parameterizations (CPs) in global high‐resolution simulations are revealed. The results show that the KE spectra exhibit high sensitivity to the CPs, mainly at mesoscales in the middle and upper troposphere. The New Tiedtke scheme produces the steepest mesoscale slope, followed by the Kain‐Fritsch scheme and then the Grell‐Freitas scheme. In general, there is a compensating relationship between latent heat released by the CP and microphysics parameterization (MP). The less latent heat released by the CP is compensated by the more latent heat released by the MP. The shallowest mesoscale spectra for the Grell‐Freitas scheme are related to the strongest downscale cascade dominated by the rotational component of the flow, and this is attributed to more latent heat released from MP enhancing the intensity of vorticity in the troposphere and producing more gravity wave activities in the lower stratosphere. Plain Language Summary: At the current horizontal resolution level of the atmospheric models, convective parameterization (CP) is crucial for representing convective clouds unresolved by model mesh and thus is still an important model component. Exploring the impacts of different CP schemes on global high‐resolution simulations is an important subject of modeling. Energy spectra have become a useful diagnostic for validating and comparing atmospheric models. Their sensitivity to CP is an important and not‐well‐studied part of this subject. This paper investigates the impact of CPs on atmospheric mesoscale kinetic energy spectra with global simulations from the Model for Prediction Across Scales. We found that the energy spectral slope and energy cascade are sensitive to the CP schemes. This is related to the complementary relationship between CP and microphysical parameterization (MP), which is also important for moist convection development and evolution. The less latent heat released by the CP, the more released by the MP. This leads to stronger vertical motion, accompanied by stronger convergence/divergence in the troposphere, thereby enhancing vortex motion. As a result, more energy is transferred from the synoptic scale to the mesoscale and more gravity waves are vertically propagated into the lower stratosphere, leading to the shallower spectra at mesoscales. Key Points: The kinetic energy (KE) spectra exhibit high sensitivity to the convective parameterizations (CPs) mainly at mesoscalesThe more latent heat released from CP, the steeper KE spectra at mesoscalesThe shallowest mesoscale KE spectra generated by the Grell‐Freitas scheme are attributed to the strongest RKE downscale cascades [ABSTRACT FROM AUTHOR]