Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method,...Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method, smoothed particle hydrodynamics(SPH) is one of the most suitable candidates for simulations of vehicle wading due to its inherent advantages in modeling free surface flows, splash, and moving interfaces. Nevertheless, the inevitable neighbor query for the nearest adjacent particles among the support domain leads to considerable computational cost and thus limits its application in 3D large-scale simulations. In this work, a GPU-based SPH method is developed with an adaptive spatial sort technology for simulations of vehicle wading. In addition, a fast, easy-to-implement particle generator is presented for isotropic initialization of the complex vehicle geometry with optimal interpolation properties. A comparative study of vehicle wading on a puddle between the GPUbased SPH with two pieces of commercial software is used to verify the capability of the GPU-based SPH method in terms of convergence analysis, kinematic characteristics, and computing performance. Finally, different conditions of vehicle speeds, water depths, and puddle widths are tested to investigate the vehicle wading numerically. The results demonstrate that the adaptive spatial sort technology can significantly improve the computing performance of the GPU-based SPH method and meanwhile promotes the GPU-based SPH method to be a competitive tool for the study of 3D large-scale FSI problems including vehicle wading. Some helpful findings of the critical vehicle speed, water depth as well as boundary wall effect are also reported in this work.展开更多
This study is focused on the forest edge flow by using numerical method.To model the effects of a forest canopy on airflow,source terms are introduced into the governing equations.The lattice Boltzmann method in conju...This study is focused on the forest edge flow by using numerical method.To model the effects of a forest canopy on airflow,source terms are introduced into the governing equations.The lattice Boltzmann method in conjunction with the standard k-εmodel is applied to solve the turbulent wind field.In order to perform the simulation on non-uniform grids,the Taylor series expansion and least square based lattice Boltzmann method(TLLBM)is adopted to improve the accuracy and computational efficiency.The present method and code are verified with an earlier forest edge simulation.A series of forest canopies are established to explore the impacts of canopy morphology on wind field.These canopies cover 3 canopy architectures and the Leaf Area Index(LAI)ranges from 2.0 to 4.0.The further study is carried out by adjusting the canopy foliage amount and the canopy architecture.The present study demonstrates the potential of lattice Boltzmann method to simulate the high Re number forest edge flow.The impacts of canopy morphology on zero plane displacement,aerodynamic roughness length,friction wind velocity,permeability coefficient,wall-shear stress are illustrated in detail.The results show that the canopy sub-layer wind field,especially the wind velocity profiles within and above the forest canopy,are mainly determined by canopy morphology.展开更多
基金supported by the Laoshan Laboratory(Grant No.LSKJ202202000)National Natural Science Foundation of China(Grant Nos.12032002,and U22A20256)Natural Science Foundation of Beijing(Grant No.L212023)。
文摘Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method, smoothed particle hydrodynamics(SPH) is one of the most suitable candidates for simulations of vehicle wading due to its inherent advantages in modeling free surface flows, splash, and moving interfaces. Nevertheless, the inevitable neighbor query for the nearest adjacent particles among the support domain leads to considerable computational cost and thus limits its application in 3D large-scale simulations. In this work, a GPU-based SPH method is developed with an adaptive spatial sort technology for simulations of vehicle wading. In addition, a fast, easy-to-implement particle generator is presented for isotropic initialization of the complex vehicle geometry with optimal interpolation properties. A comparative study of vehicle wading on a puddle between the GPUbased SPH with two pieces of commercial software is used to verify the capability of the GPU-based SPH method in terms of convergence analysis, kinematic characteristics, and computing performance. Finally, different conditions of vehicle speeds, water depths, and puddle widths are tested to investigate the vehicle wading numerically. The results demonstrate that the adaptive spatial sort technology can significantly improve the computing performance of the GPU-based SPH method and meanwhile promotes the GPU-based SPH method to be a competitive tool for the study of 3D large-scale FSI problems including vehicle wading. Some helpful findings of the critical vehicle speed, water depth as well as boundary wall effect are also reported in this work.
基金This work was supported by the National Key R&D Program of China(No.2016YFC0500901).
文摘This study is focused on the forest edge flow by using numerical method.To model the effects of a forest canopy on airflow,source terms are introduced into the governing equations.The lattice Boltzmann method in conjunction with the standard k-εmodel is applied to solve the turbulent wind field.In order to perform the simulation on non-uniform grids,the Taylor series expansion and least square based lattice Boltzmann method(TLLBM)is adopted to improve the accuracy and computational efficiency.The present method and code are verified with an earlier forest edge simulation.A series of forest canopies are established to explore the impacts of canopy morphology on wind field.These canopies cover 3 canopy architectures and the Leaf Area Index(LAI)ranges from 2.0 to 4.0.The further study is carried out by adjusting the canopy foliage amount and the canopy architecture.The present study demonstrates the potential of lattice Boltzmann method to simulate the high Re number forest edge flow.The impacts of canopy morphology on zero plane displacement,aerodynamic roughness length,friction wind velocity,permeability coefficient,wall-shear stress are illustrated in detail.The results show that the canopy sub-layer wind field,especially the wind velocity profiles within and above the forest canopy,are mainly determined by canopy morphology.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102365,91752202 and 11472016)Luoqin Liu was supported by the Hundred Talents Program of the Chinese Academy of Sciences(CAS).