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Numerical Simulation of Aeroacoustic Problems

Delfs, J. und Yin, J. (1999) Numerical Simulation of Aeroacoustic Problems. In: Proceedings ODAS 99. ONERA-DLR Aerospace Symposium, Paris (fr), 21.-24.06.1999.

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Kurzfassung

The present paper investigates the numerical methods used to predict aerodynamically generated noise, more specifically airframe noise. Here, airframe noise is understood as noise, which is generated due to the interaction of turbulence-related vorticity disturbances with geometric inhomogeneities of an aerodynamic body. Such interaction may take place directly or indirectly through a previously occuring hydrodynamic instability of the flow field. First, the main mechanisms of airframe noise are discussed. Based on these physical considerations the potentially suitable computation approaches to airframe noise are identified and assessed w.r.t. limitations. Modern CAA (Computational Aeroacoustics) techniques are presented. Since (as opposed to using acoustic wave equations) the dynamics of all types of waves (pressure-, vorticity-, entropy-) can be simulated using Euler's equations, generally, approaches based on the Euler equations can be employed to compute not only the noise propagation but its very generation as well. The numerical solution of Euler's equations on a computational grid generally necessitates the use of some sort of artificial selective damping in order to render the solutions stable. The paper discusses the role, artificial selective damping may play for the sound generation. The effect of these terms are understood when using one of the aeroacoustic analogy equations or e.g. Möhring's acoustic wave equation. Examples are given, showing how artificial selective damping "contributes" to computational noise. Typical aeroacoustic problems relating to airframe noise are solved numerically employing the DRP-scheme of Tam.

Dokumentart:Konferenzbeitrag (Paper)
Zusätzliche Informationen: LIDO-Berichtsjahr=1999,
Titel:Numerical Simulation of Aeroacoustic Problems
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Delfs, J.NICHT SPEZIFIZIERT
Yin, J.NICHT SPEZIFIZIERT
Datum:1999
Erschienen in:Proceedings ODAS 99
Status:veröffentlicht
Stichwörter:computational aeroacoustics, CAA, airframe noise, noise generation, edge noise mechanism, artificial selective damping, Euler equations, signal-to-numerical-noise ratio, DRP-scheme
Veranstaltungstitel:ONERA-DLR Aerospace Symposium, Paris (fr), 21.-24.06.1999
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Luftfahrt
HGF - Programmthema:L VU - Luftverkehr und Umwelt (alt)
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L VU - Luftverkehr und Umwelt
DLR - Teilgebiet (Projekt, Vorhaben):L - Leiser Luftverkehr (alt)
Standort: Köln-Porz , Braunschweig , Göttingen
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Institut für Entwurfsaerodynamik
Hinterlegt von: Claudia Grant
Hinterlegt am:16 Sep 2005
Letzte Änderung:14 Jan 2010 20:08

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