Computational aeroacoustics of viscous low speed flows using subgrid scale finite element methods

Abstract

A methodology to perform computational aeroacoustics of viscous low speed flows in the framework of stabilized finite element methods is presented. A three-step procedure is followed that makes use of Lighthill's acoustic analogy. In the first step, the incompressible Navier-Stokes equations are solved to obtain the flow velocity field. In the second step, the acoustic source term is computed from this velocity field and then Fourier transformed to the frequency domain. Finally, the acoustic pressure field is obtained by solving the Fourier transform of Lighthill's acoustic analogy. All equations in the formulation are solved using subgrid scale stabilized finite element methods. The main ideas of the subgrid scale numerical strategy are outlined and its benefits when compared to the Galerkin approach are described. As numerical examples, the aerodynamic noise generated by flow past a two dimensional cylinder and by flow past two cylinders in parallel arrangement are addressed.