Numerical analysis of the low-frequency noise emitted from a cylindrical and plane boundary layer

Spatial direct numerical simulations are used to study the development of turbulent structures and the resultant sound emission mechanism in a compressible boundary layer. Disturbances of compressible isotropic turbulence with the amplitude change for spanwise direction are superimposed on the laminar profile at the inlet boundary layer in the computational box. Simulation results show that the inlet disturbances affect the transition region and suppress the low-frequency velocity/pressure fluctuations in a subsonic cylindrical boundary layer.