Applications of a Cartesian mesh boundary-layer approach for complex configurations

This paper examines the performance of a coupled Euler boundary-layer approach in simulating viscous flows around a variety of aerospace configurations. The method combines an established multilevel Cartesian-mesh Euler solver with a transpiration boundary condition to account for the boundary-layer displacement thickness. This boundary condition is set via a strip-wise solution of the 2D boundary-layer equations which uses the inviscid solution as a driver. The implementation uses local flow topology to establish attachment and separation and an elliptic solve on the surface triangulation to couple surface transpiration velocities back to the inviscid solver. While interacting boundary-layer (IBL) approaches are not necessarily new, the current approach is strongly focused on complex configurations and the implementation includes some novel techniques for coping with geometric complexity, markedly improving its utility, and removing the need for additional viscous corrections. The use of IBL solvers is well established for transport aircraft configurations, and the current work examines the success of the technique for such cases and explores its utility outside this class of problems. The investigations demonstrate the technique's performance with both single-point and parametric studies on 2D supercritical airfoils, isolated wings, finned-missiles, and full-aircraft configurations. Results on the NACA RM-10 showed good agreement over a range of transonic and supersonic Mach numbers. Simulations on the DLR F-4 wing-body yielded aerodynamic force coefficients that agreed well with established results from the 1st AIAA Drag Prediction Workshop over a range of conditions. The discussion of these numerical results highlights regions of continued research.