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The relationship between the presented work and energy conservation is direct and indirect. Most of the literature related to energy-saving focuses on reducing the aerodynamic drag of cars, which typically leads to the appearance of vehicle motion instabilities at high speeds. Typically, this instability is compensated for by moving aerodynamic body components activated above a certain speed and left in that position until the vehicle speed drops. This change in vehicle configuration results in a significant increase in drag at high velocities. The presented study shows a fully coupled approach to fluid–structure interaction analyses of a car during a high-speed braking-in-turn manoeuvre. The results show how the aerodynamic configuration of a vehicle affects its dynamic behaviour. In this work, we used a novel approach, combining Computational Fluid Dynamics (CFD) analysis with the Multibody Dynamic System. The utilisation of an overset technique allows for car movement in the computational domain. Adding Moving Reference Frame (MRF) to this motion removes all restrictions regarding car trajectory and allows for velocity changes over time. We performed a comparative analysis for two aerodynamic configurations. In the first one, a stationary rear airfoil was in a base position parallel to a trunk generating low drag. No action of the driver was assumed. In the second scenario, brake activation initiates the rotation of the rear airfoil reaching in 0.1 s final position corresponding to maximum aerodynamic downforce generation. Also, no action of the driver was assumed. In the second scenario, the airfoil was moving from the base position up to the point when the whole system approached its maximum downforce. To determine this position, we ran a separated quasi-steady analysis in which the airfoil was rotating slowly to avoid transient effects. The obtained results show the importance of the downforce and load balance on car stability during break-in-turn manoeuvres. They also confirm that the proposed methodology of combining two independent solvers to analyse fluid–structure phenomena is efficient and robust. We captured the aerodynamic details caused by the car's unsteady movement. [ABSTRACT FROM AUTHOR]

A coupled analysis of agent behavior and Computational Fluid Dynamics (CFD) model is applied to investigate the fire evacuation effectiveness in a popular metro station in Guangzhou, China. Due to the high density and complexity of traffic, the concept of Required Safe Escape Time and Available Safe Escape Time (RSET/ASET), which is more flexible and adaptable than the "6 minutes" principle, is applied in the safety assessment of fire evacuation. To pursue a stable simulation of the coupled model, the standard Critical Radiant Flux is used to deter the tenability criteria for exposure to fire and heat. Various related factors, including the fire location, the Heat Release Rate (HRR) of fire, the crowd density, and the operation mode of escalators, are analyzed through a series of simulations. Results indicate that the interaction between fire and humans should not be neglected in the evacuation simulation. Both the fire location and the crowd density have a significant effect on the evacuation, while the HRR of fire has a minor impact. When the accident happens at the entrance of an escalator, RSET is 58.3% longer than that when the accident occurs in the middle of the platform. RSET grows with the increase of the crowd density linearly. Besides, the evacuation efficiency could be partly improved by changing escalators that usually operate in the descending mode into ascending mode. [ABSTRACT FROM AUTHOR]

Technique of the nonlinear numerical analysisof the air-supported structures including fluid-structural interaction (FSI) has been described in the present paper. Numerical simula- tion of the tunnel test of large-scale air-supported model has been carried out as example of using this technique. The comparison of the experimental and numerical resultsdemonstrated applicability of proposed technique to the considered class of problems. Opportunity to de- velop this technique to the more complicated and advanced problems has been shown, too.

The failure of reactor pressure vessel (RPV) during a severe accident of light water reactors is a thermal fluid-structure interaction (FSI) problem which involves melt pool heat transfer and creep deformation of the RPV. The present study is intended to explore a reliable coupling approach of thermo-fluid-structure analyses which will not only be able to reflect the transient thermal FSI feature, but also apply the advanced models and computational platforms to melt pool convection and structural mechanics, so as to improve simulation fidelity. For this purpose, the multi-physics platform of ANSYS encompassing Fluent and Structural capabilities was employed to simulate the fluid dynamics and structural mechanics in a coupled manner. In particular, the FOREVER-EC2 experiment was chosen to validate the coupling approach. The natural convection in melt pool was modeled with the SST turbulence model with a well-resolved boundary layer, while the creep deformation for the vessel made of 16MND5 steel was analyzed with a new three-stage creep model (modified theta projection model). A utility tool was introduced to transfer the transient thermal loads from Fluent to Structural which minimizes the user effort in performing the coupled analysis. The validation work demonstrated the well-posed capability of the coupling approach for prediction of the key parameters of interest, including temperature profile, total displacement of vessel bottom point and the evolution of wall thickness profile in the experiment. [ABSTRACT FROM AUTHOR]

This paper deals with a 16-pole, 18-slot fractional-slot concentrated-winding permanent-magnet synchronous machine (PMSM) for articulated robot applications considering several multiphysics analyses. Optimized PMSMs are compared analytically and experimentally considering electrical and mechanical aspects. The electrical and mechanical analysis results are well matched with the experimental results in terms of the efficiency and temperature. The design, analysis and experiment with the PMSM for articulated robot applications were performed successfully. [ABSTRACT FROM AUTHOR]

Abstract The aerodynamic heating of an inflatable reentry vehicle, which is one of the innovative reentry technologies, was numerically investigated using a tightly coupled approach involving computational fluid dynamics and structure analysis. The fundamentals of a high-enthalpy flow around the inflatable reentry vehicle were clarified. It was found that the flow fields in the shock layer formed in front of the vehicle were strongly in a chemical nonequilibrium state owing to its low-ballistic coefficient trajectory. The heat flux tendencies on the surface of the vehicle were comprehensively investigated for various effects of the vehicle shape, surface catalysis, and turbulence via a parametric study of these parameters. In addition, based on the present results of the computational approach, a new heating-rate method was developed to calculate the heat flux of the nonequilibrium flow. It was demonstrated that the method could well-reproduce the heat flux on the inflatable reentry vehicle. Highlights • Aerodynamic heating of inflatable aeroshell is investigated by a computational approach. • Surface heat flux tendencies during reentry are clarified using a parametric study. • A new heating-rate method is developed to evaluate aerodynamic heating with high accuracy. [ABSTRACT FROM AUTHOR]

The coupled fluid/solid heat transfer computations are performed to predict the temperatures reached in the rotating disc systems. An efficient finite element analysis (FEA) and computational fluid dynamics (CFD) thermal coupling technique is developed and demonstrated. The thermal coupling is achieved by an iterative procedure between FEA and CFD calculations. In the coupling procedure, FEA simulation is treated as unsteady for a given transient cycle. To speed up the thermal coupling, steady CFD calculations are employed, considering that fluid flow time scales are much shorter than those for the solid heat conduction and therefore the influence of unsteadiness in fluid regions is negligible. To facilitate the thermal coupling, the procedure is designed to allow a set of CFD models to be defined at key time points/intervals in the transient cycle and to be invoked during the coupling process at specified time points. The computational procedure is applied to predict heat transfer characteristics of a free rotating disc. [ABSTRACT FROM AUTHOR]

New computational approach for hydrogen leakage with wall crack propagation problem was conducted by using a hybrid of the coupled particle and Eulerian methods. This computational method provides useful safety information for predicting crack propagation and hydrogen leakage in pressure vessels as an important part of assessing hydrogen as an energy vector. The present computational analysis procedures consisted of two main parts. The first part was crack propagation analysis of a thin square plate, which simulated the wall of a high-pressure hydrogen vessel by using a particle method. The crack propagation was analyzed in high-pressure tank walls under two different types of initial conditions, and in both cases, the direction of crack propagation was freely determined by the direction of the stress field. This confirms the superiority of particle methods for modeling destructive phenomena. After the crack propagation analysis, the particle location and coordinate data of the barrier wall were converted to Euler mesh data. The geometric data of particle location were fitted to Euler numerical space, which was used for simulating high-pressure hydrogen leakage into air at atmospheric pressure. The differences and features of hydrogen diffusion during hydrogen leakage were analyzed for two types of wall data and two types of boundary conditions, as a result, the effect of wall boundaries on the hydrogen concentration distribution was computationally predicted. [ABSTRACT FROM AUTHOR]

This study conducted a CFD-2D coupled analysis of a suspension bridge subjected to wind loads. Previous studies found that rotational oscillation was due to differences in the restoring force at hanger cables and could generate torsional oscillations. However, due to uncertain external force terms, the previous studies could not be applied to analyze actual structures. To enable application in a real design process, this study proposed a methodology for determining the external force terms. The external force terms were determined with CFD, and a moment force term was added to equations of motion derived from dynamic equilibrium conditions. All constants and properties were calculated from an assumed cross section of superstructure. This methodology can be used not only to avoid torsional resonance but also in preliminary analysis in the bridge design stage. [ABSTRACT FROM AUTHOR]

With the help of numerical simulation a new high-pressure hydraulic axial pump has been developed at Gdansk University. Its unique feature is the total independence of a pressure switching mechanism, which saves weight and provides the possibility to control the pump by computer. To avoid noise and possible damage of the pump through harmful pressure peaks an additional chamber equipped with an elastic wall was introduced. Numerical simulation of the fluid-structure interaction occurring at the elastic wall proved to be very insightful for the development of the new pump. Results of the coupled simulation - using Fluent, Abaqus and Fraunhofer SCAI's multiphysics software MpCCI - are presented in this paper. [ABSTRACT FROM AUTHOR]