Quasi-Simultaneous Viscous-Inviscid Interaction for Transonic Airfoil Flow

Following Prandtl, a viscous-inviscid interaction (VII) method is presented, where the flow field is divided into a viscous shear layer and an inviscid outer region. Their coupling is performed with the quasi-simultaneous approach, making use of an appropriately chosen interaction law. Firstly, an engineering example of transonic airfoil flow is presented, in which the interaction law is based on thin-airfoil theory. Thereafter, the VII coupling approach is analyzed by mathematical means, leading to a strongly simplified interaction law, yet allowing calculations beyond maximum lift simply starting from scratch