Abstract
Numerical results of HPC simulation that investigate the aerodynamics and the assessment of the running stability of road vehicles are presented in this study. FrontFlow/red-HPC is utilized to predict the flow around road vehicles. This code is based on the open source CFD software FrontFlow/red, and is developed specifically for road vehicle aerodynamics under HPC environments. Two applications of the CFD code are shown in this paper. One is the modal analysis for flow structures which cause the fluctuating lift in the range of below 5Hz. This frequency range is close to the natural frequency of the vehicle’s suspension and damper system, and it may cause resonance. Dynamic Mode Decomposition is used to extract the flow structures oscillating in the specific frequency. The results indicated that the flow around the rear trunk-deck and rear underbody contributed to the fluctuating lift. The other shows the need for a two-way coupled simulation of the unsteady aerodynamics and the vehicle motion. A commercial motion solver is coupled with FrontFlow/red-HPC in the coupled simulation framework. This framework is applied to predict the vehicle’s trajectory when vehicles are subjected to gusty crosswinds. Then, the results of the conventional one-way coupled simulation and two-way coupled simulation are compared to investigate the validity of this coupled framework.
