Numerical Simulation Study About Aeroacoustics In Shear Flows

According to the integrated compressible fluid mechanics equations together with eigenvalue analysis, the new non-reflecting boundary conditions for simulating the all directions radiation of disturbance waves was provided. In this paper, aeroacoustics in shear flows is studied with the new boundary conditions using numerical simulation method and the effect of shear flows for radiation of disturbance is also studied. The governing equations are the compressible conservation Navier-Stokes equations together with the ideal gas law, constant equation. A fifth-order weak upwind compact finite difference scheme is chosen for evaluating convection term and a sixth-order central compact finite difference scheme is used for evaluating viscosity term. The Gauss' distributing pressure pulses are chosen for simulating noise sources.The conclusions from the results of numerical simulation are followed:With the new boundary conditions, the disturbance waves in still flows, uniform flows and uniform shear flows were simulated. The results show that the new boundary conditions given in this paper are more appropriate.The simulation results of the computation of uniform shear flows and compressible mixing layer show that the grads of velocity will influence the radiation of disturbance waves in shear flows and the disturbance waves can radiate through the mixing layer, but the disturbance waves will radiate in other directions.