PhD defense - A. Fosso Pouangué

Compact Finite Volume Scheme : Application to the computational aeroacoustics of subsonic jets

Delivered by Université Pierre et Marie Curie Paris
Speciality: Mechanics, acoustics, electronics


April 5, 2011 - CERFACS

The developed numerical schemes are based on ?ux computation using directional implicit (compact) interpolation in the physical space. Two formulations are proposed. The more general formulation allows to handle meshes with strong shape and size variations. Special care is taken for multi-block boundaries. To reduce computational costs, the schemes are made explicit on these boundaries. Di?erent formulations are studied to insure that the precision, low dispersion, low dissipation, and stability of the schemes are preserved. However, adding of arti?cial selective dissipation or ?ltering is necessary to stabilize computations. A compact arti?cial selective dissipation operator and a compact ?lter are studied. All these tools are implemented in the elsA code to perform subsonic jet noise studies in an industrial context. The Computational Aeroacoustics strategy used is an hybrid approach coupling large eddy simulation for aeroacoustic sources and Ffowcs-Williams and Hawking analogy for acoustic propagation. Additional numerical tools are implemented in elsA : low dispersive and low dissipative time advance schemes and non-re?ecting boundary conditions. The subgrid-scale modeling is implicit, assuming that the energy transfer from large scales to small scales is provided by either the dissipation operator or the ?lter. The whole set of tools is used for the study of two con?gurations of subsonic jets. The ?rst con?guration is an isothermal jet with 0.9 Mach number and 4 × 105 Reynolds number, computed on a stretched cartesian grid. The second con?guration is an isothermal jet with 0.3 Mach number and 3.21 × 105 Reynolds number computed on an O-H grid including the nozzle geometry. The results of these studies allow to validate the bene?ts of the developments but also to identify limits and aspects to improve.

C. Bailly	Professor - Ecole Centrale de Lyon	Referee
C. Lacor	Professor - Vrije Universiteit, Brussels	Referee
B. Caruelle	Doctor Engineer, Airbus France	Member
H. Deniau	Doctor Engineer, CERFACS	Member
R. Marchiano	Assistant Professor, Université Pierre et Marie Curie Paris VI	Member
S. Moreau	Professor, University of Sherbrooke	Member
P. Sagaut	Université Pierre et Marie Curie Paris VI	Advisor

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