Numerical Simulation of Aeroacoustics Generated by Flow around 30P30N High-lift Aerofoil using Hybrid CFD/BEM approach

Abstract

In this study, we have performed the acoustic simulation generated by the flow around the 30P30N airfoil with a slat and a flap by means of Boundary element Method using quadrupole sources extracted from the unsteady CFD simulations. The CFD simulations are performed using Ansys Fluent with LES Dynamic Model, and compressible flow fields have been solved. The attack angles of the airfoil are 5.5 and 9.5 degree. When the BEM calculation for the acoustic propagation was performed, the FMM (Fast Multipole Method) and FMBEM were used to calculate quickly the contributions from the quadrupole sources and acoustic propagation, reflection and diffraction on the boundaries, those are the walls of the 30P30N airfoil. The results of the acoustic simulations show a relatively good agreement with the experimental data and other researchers' simulation results. The directivities of the acoustic pressure for the primary peak frequency are shown and they depend on the attack angle of the airfoil. The far-field SPL also depends on the attack angle of the airfoil and decreases as the attack angle increases. We have also investigated the quadrupole sources in frequency domain, and the results showed that the quadrupole sources at far-field SPL peak frequencies near the wake of slat and the suction side of the main element of the airfoil are stronger than those in other regions.