B. Basel, C.-D. Munz, M. Grünewald

The application of numerical simulation in aerocaoustics has been considerable augmented in the last years. New numerical methods and supercomputers allow to calculate a nearly exact flow around complex bodies. For the calculation of flow generated acoustical sources it is necessary to obtain a high precision in the dynamic flow field simulation. LES is an appropriate way to achieve this accuracy at high Reynolds numbers. To simulate the propagation of acoustical waves the 3D linearized Eulerian Equations in conservative form are solved with a Finite Difference Method on a special grid. The advantage of the grid presented is that reflections from the body are taken into account and that it has a very low dispersion with the DRP scheme. Strong reflections destabilize the solution at the outer boundaries of the grid. One possibility to avoid these is to absorb the outgoing waves in the vicinity of these boundaries. Conventional methods need to take into account the angle between the wave front and the grid, which in general is cumbersome and time consuming to be calculated. A new PDE is presented for the absorbing boundaries which does not require the information about the angle so speeding up the calculations. Additionally a comparison between Finite Element and FD shows the advantage in accuracy of the latter. LES is used to calculate the flow for the examples presented. In the first approach the wave field is calculated with simulated acoustic sources. In a second simulation the acoustic sources are derived from the dynamic flow data. Higher order sources as quadrupoles are considered.

International Workshop on "LES for Acoustics"; Göttingen; 2002

Conference Abstract

englisch

A4, 1 Seiten

DGLR-Bericht, 2002, 2002-03, LES for Acoustics - Proceedings; S.1-1; 2002; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

aeroacoustics, large eddy simulation

Bibliothek

2002