Note on the inviscid stability of flow over a compliant wall

Abstract

This paper is concerned with the linear inviscid stability of parallel flow over a compliant or flexible wall. A Fjortoft-type criterion providing a necessary condition for instability in terms of the basic velocity field and its second-order derivative is established. This criterion assumes a simple form for basic flows with zero velocity at the wall. For the latter flows, another necessary condition for stability is given. The results are helpful in the search for unstable modes in flow over a compliant wall.