ANALYSIS OF A FEM BEM COUPLING METHOD FOR TRANSONIC FLOW COMPUTATIONS/

A sensitive issue in numerical calculations for exterior flow problems , e.g. around airfoils, is the treatment of the far field boundary con ditions on a computational domain which is bounded. In this paper we i nvestigate this problem for two-dimensional transonic potential flows with subsonic far held flow around airfoil profiles. We take the artif icial far field boundary in the subsonic flow region. In the far field we approximate the subsonic potential flow by the Prandtl-Glauert lin earization. The latter leads via the Green representation theorem to a boundary integral equation on the far field boundary. This defines a nonlocal boundary condition for the interior ring domain. Our approach leads naturally to a coupled finite element/boundary element method f or numerical calculations. It is compared with local boundary conditio ns. The error analysis for the method is given and me prove convergenc e provided the solution to the analytic transonic flow problem around the profile exists.