Abstract
Spatial direct numerical simulations are used to study the development of turbulent structures and the resultant sound emission mechanism in a compressible boundary layer, for a high-speed train model conducted in a moving model facility, where the free stream velocity is 500Km/h (corresponding Mach number is 0.41). Disturbances of compressible isotropic turbulence are superimposed on the laminar profile at the inlet boundary layer in the computational box. The Reynolds number at the inlet based on the displacement thickness is 1640, which meets the measurement of the boundary layer undergoing transition. Simulation results show that the inlet disturbances affect the transition and the low-frequency velocity/pressure fluctuations. Low frequency waves are generated in the turbulent boundary layer and radiated toward an open area.
