Overview

Raphael Lardat, Romuald Carpentier and Alain Dervieux
INRIA, Sophia-Antipolis, France

Bruno Koobus
Department of Mathematics, Universit de Montpellier II, France

Eric Schall
IUT G nie Thermique et Energ tique, Universit de Pau, France

Charbel Farhat
Department of Aerospace Engineering Sciences, University of Colorado at Boulder, USA

Jean-Fran ois Guery and Patrick Della Pi ta
Soci t Nationale des Poudres et Explosifs, Vert le Petit, France

1. Introduction

Increasing scales of artifacts lead frequently to various unexpected difficulties. It is well known that bigger aircraft, for example, have to manage with much wider structural deformations, which are consequences of the coupling between structural and aerodynamical effects. In the ARIANE5 programme, the two lateral boosters are about one order of magnitude heavier than those of ARIANE4, and this motivates several prospective studies in order to ensure that performances and safety will not be affected (or how it will be affected) by new coupling phenomena.

Large Solid Rocket Motors (SRM) are generally not made of one piece, but involve segments often separated by thermal inhibitors. During the combustion of the solid propellant, the inhibitors become obstacles to the flow which may induce vortices. Even if this mechanism is not the only one leading to vortex-shedding, the passing of vortices through the outlet nozzle induces a fluctuation of internal pressure, and therefore of thrust, which leads to a rather complex aero-acoustic coupling showing a variety of quasi-periodic solution [CAR 99] and [CAR 98]. This has been analyzed in the ASSM research and technology French programme for which physical...