On the treatment of the Kutta-Joukowski condition in transonic flow computations

A finite clement-boundary element coupling procedure is applied to the comp utation of a transonic, compressible full potential flow past an airfoil. W e require the Kutta-Joukowski condition as continuity of the press re field at the trailing edge. Under the assumption of subsonic Slow at the trailin g edge and using classical regularity results for the solutions of elliptic first order systems, we prove the Holder continuity of the velocity in a v icinity of the trailing edge and get a local representation formula for the velocity. The Kutta-Joukowski condition enforces that the so-called stress intensity factor in this representation vanishes. The numerical FEM-BEM co upling procedure is executed in spaces of finite element functions characte rized by the linear side condition of vanishing approximate stress intensit y factors. The linear side condition is formulated in, terms of the Maz'ya functional for the stress intensity factor. Detailed numerical implementati on and numerical results are presented. MSC (1991): 65N30, 30G20. 65N38, 76 H05, 49M10, 35L67, 33J25, 65N50.