This paper is devoted to the study of a coupled system which consists ofa wave equation and a heat equation coupled through a transmission conditionalong a steady interface. This system is a linearized model forfluid-structure interaction introduced by Rauch, Zhang and Zuazuafor a simple transmission condition and by Zhang and Zuazua for anatural transmission condition. Using an abstract theorem of Burq and a new Carleman estimate proved near the interface, wecomplete the results obtained by Zhang and Zuazua and by Duyckaerts.We prove, without a Geometric Control Condition, a logarithmic decayof the energy.
