Kobe University, Kobe
APPLIED AERODYNAMICS SIMULATION ON THE K COMPUTER, FROM GOLF BALL TO URBAN WIND
Large-Eddy Simulation based on the unstructured and the hierarchically structured grid systems specially tuned on the K computer was developed, and was applied to the aerodynamics simulation of golf ball, road vehicle, and high-rise building in Tokyo urban area.
For the sphere aerodynamics including the golf ball, special focus was on the reproduction of the drag crisis by allocating very fine unstructured mesh near the wall, and good agreement with experimental data was achieved. Magnus effect acting on the sphere and its dependence on the Reynolds number was also investigated.
For the road vehicle aerodynamics, the framework of realizing massively parallel simulation using up to billions of unstructured as well as tens of billions of hierarchically structured meshes was developed by using the conventional pre-/post- processing software in industry. Then full-scale road vehicle aerodynamics simulation with very complicated geometry reproduced from the real CAD data was conducted and excellent agreement of aerodynamic drag with wind-tunnel data was realized. The method was also implemented to reproduce the unsteady aerodynamics during real driving condition by coupling the aerodynamics with vehicle’s 6DoF motion.
For the high-rise building in Tokyo area, atmospheric turbulence boundary layer developing over the Tokyo area of 23kmx23km region was reproduced with its minimum resolution less than 1m by adopting hierarchically structured grids of total of more than 20 billion meshes. Then transient wind load including max. and min. value of the surface pressure acting on the target high-rise building was evaluated.