PhD defense - F. Sicot

Efficient Simulations of Time-Periodic Unsteady Flows in Turbomachinery 

Delivered by Ecole Centrale de Lyon
Speciality: Mecanics, Energetics, Civil Engineering and Acoustics

October 12, 2009 - CERFACS

Many industrial applications involve flows periodic in time. Flutter prediction or turbomachinery flows are some examples. Such flows are not simulated with enough efficiency when using classical unsteady techniques as a transient regime must be by-passed. New techniques, dedicated to time-periodic flows and based on Fourier analysis, have been developed recently. These methods, called harmonic balance, cast a time-periodic flow computation in several coupled steady computations, corresponding to a uniform sampling of the period. Their efficiency allow to get a precision good enough for engineering but much faster than classical nonlinear time-marching algorithms. 

The present study aims at imlementing one of these, the Time Spectral Method, in the ONERA solveur elsA. It is extended to an arbitrary lagrangian/eulerian formulation to take into mesh deformation for aeroelasticity applications. New implicit algorithms are developped to improve robustness. The TSM is successfully validated on external aerodynamic applications. Turbomachinery flows necessitate complex space and time interpolations ro reduce the computational domain to a single blade passage per row regardless of its geometry. Some applications in rotor/stator interactions and aeroelasticity are presented.

P. Cinella	Professor - ENSAM, Paris	Referee
C. Hirsch	Professor (emeritus) - Vrije Universiteit, Bruxelles	Referee
J.F. Boussuge	Research engineer - CERFACS, Toulouse	Member
A. Dugeai	Research engineer - ONERA, Châtillon	Member
S. Moreau	Professor - University of Sherbrooke	Member
F. Leboeuf	Professor - Ecole Centrale - Lyon	Advisor
M. Roger	Professor - Ecole Centrale - Lyon	Advisor