How to stabilize instabilities in the boundary layer around an airfoil
by
Philippe Destuynder
Chaire de Calcul Scientifique, CNAM, Paris
Coauthors: Emmanuelle Gout d'Henin

At the origin of our analysis is the challenge : "How to stabilize instabilities in the boundary layer around an airfoil." As a matter of fact, it has been proved by several authors, using an experimental approach, that these flow instabilities can reduce significantly the drag force. The full modelling of the mechanical phenomenon is still out of our reach. Hence we suggest an aeroacoustic formulation. Using piezo-devices sticked on a flexible part of an airfoil, we adjust the control law in order to develop and to maintain surface acoustic waves. The former ones are known as Stoneley waves and their analysis can be done precisely. This enables one to optimize the strategy that we are talking about. Then the transfer of kinetic energy to boundary layer instabilities is ensured by a resonance mechanism, because the Stoneley waves are prescribed at the right frequency in order to stimulate the coupling with flow instabilities, the frequency of which is known. The goal of this paper is to characterize the control procedure that we suggest. Several numerical simulations will show the efficiency of the strategy from the theoretical point of view.

Date received: February 21, 2000

Copyright © 2000 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cads-88.