Low-Order Finite-Volume Based Riemann Solver for Application to Aeroacoustic Problems

Abstract

The current study focuses on the development of a three-dimensional flow and aeroacoustic solver developed in a finite-volume framework which uses similar, dense meshes for both flow and acoustics while using low-order schemes from the finite volume framework to minimize the points per wavelength, overcomes interpolation errors between flow and acoustic meshes, since one-to-one mesh mapping will be applied, minimize the computational time for the acoustic loop with respect to the fluid flow loop and provides a practical, easy to use integrated numerical tool. As dispersion errors are common within this computational framework, Riemann fluxes are used to solve the linearized Euler equations with unsteady quadrupole and dipole sources. A coupling scheme is presented and common issues with boundary conditions, mesh topology and sub-cycling are discussed. Various verification and validation test cases show the expected behavior and trends with respect to analytic and reference results. An application case is presented, where airfoil self-noise is determined around a beveled flat plate.