Prediction of flow induced noise near a rigid body at low Mach numbers.

Abstract

For low Mach number flow around a solid body, the far‐field sound pressure is dominated by dipole sources comparing with the monopole and quadruple components. The dipole sources are created by the unsteady surface pressure distributions due to the presence of a turbulent boundary layer in the vicinity of the solid body. The far‐field sound pressure can be calculated by integrating the time derivative of the wall‐pressure fluctuations at the surface of the rigid body. Recent development in computational fluid dynamics (CFD) brings a powerful tool for predicting unsteady turbulent flow fields and the generation mechanism of aerodynamic noise. The current study investigates the use of improved CFD method to accurately simulate the flow fields near a solid body. The information of the flow field is then used to calculate the far field sound pressures. Extensive computations have been conducted to calculate the noise induced by the flow over a circular cylinder and an automobile’s rear view mirror. The calculated sound pressure levels have shown to agree well with published experimental results. [Work sponsored by the China Scholarship Council.]