M. Terracol, E. Manoha, C. Herrero, P. Sagaut

This paper describes a new step in the development of a Computational AeroAcoustics (CAA) process whose general long term objective is the numerical prediction of the aerodynamic sound radiated by the airframe of large aircraft at approach, and especially the noise generated by deployed high lift devices such as slats and flaps. The proposed hybrid process combines CFD (Computational Fluid Dynamics) techniques and acoustic numerical methods, each one being adapted to a particular domain in which specific physical fluid mechanisms are simulated solving an adequate set of equations. In this process, (i) the nearfield unsteady flow is computed via a compressible three-dimensional unsteady CFD computation, (ii) then CFD-computed perturbations are injected at the inner boundary of a larger domain in which the outward propagation of small perturbations over a non-uniform mean flow is simulated using Euler equations, and finally, (iii) the acoustic field radiated at the external boundary of the Euler domain becomes the entry data of a Kirchhoff integration which provides the noise radiated in the far field. In the first part of this paper, the three steps of this hybrid process are successively applied to the numerical prediction of the noise radiated by a three dimensional NACAOOI2 airfoil with a blunted trailing edge. In this case, the 3D local unsteady flow is computed via LES (Large Eddy Simulation). However, successive computations require expensive temporary data storage and complex code interfacing, so the ultimate goal is a full integrated process in which both the CFD and the acoustic methods would be run in a unique computation. The second part of the paper describes undergoing works that aims towards this objective. An early numerical simulation is presented, in which the DNS (Direct Numerical Simulation) of the flow around a 2D NACA0012 airfoil with a sharp trailing edge is simultaneously coupled with Euler propagation techniques.

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

Conference Paper

englisch

A4, 10 Seiten

DGLR-Bericht, 2002, 2002-03, LES for Acoustics - Proceedings; S.1-10; 2002; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

large eddy simulation

Bibliothek

2002