A few references on the topic of boundary layer-inviscid flow coupling are given in Chapter 6. In this appendix we shall briefly explain a simple procedure of this flow coupling procedure. To understand the process of coupling the Euler and integral boundary solutions we shall consider a typical flow pattern around a wing as shown in Fig. E.1. Both turbulent and laminar regimes are shown in this figure.

We summarize the procedure as follows:

Step 1. Solve the Euler equations in the domain considered around the aerofoil. Here any mesh can be used independently of the mesh used for the boundary layer solution. The solution thus obtained will give a pressure distribution on the surface of the wing.

Step 2. Solve the boundary layer using an integral approach over an independently generated surface mesh. If the surface nodes do not coincide with the Euler mesh, the pressure needs to be interpolated to couple the two solutions. The laminar portion near the boundary (Fig. E.1) is calculated by the Thwaites compressible method and the turbulent region is predicted by the lag-entrainment integral boundary layer model.

Step 3. The Euler and integral solutions are coupled by transferring the outputs from one solution to the other. As indicated in Fig. H.1, direct and semi-inverse couplings can be used for different regions. The semi-inverse coupling is introduced here mainly to stabilize the solution in the turbulent region close to separation. Figure H.2 shows the flow diagrams for the present boundary layer-inviscid...