Estimation of three-dimensional boundary layer velocity profiles on swept wings and blended wing bodies

A rapid process of boundary layer (BL) velocity profile reconstruction is frequently required for wing surface drag estimation or for aircraft engine intake design. With the Viscous Full-Potential (VFP) method, accurate prediction of local boundary layer parameters can be provided with high speed. However, no information is given concerning velocity distribution within the boundary layer. Existing boundary layer reconstruction methods have been applied to five test cases of different freestream Mach number range, and comparisons have been carried out between their results and experimental velocity profiles. A new optimized method which can give reliable results for both the streamwise and the crossflow directions at different subsonic airspeed has then been developed. Comparisons have then been performed, for two of these test cases, between velocity profiles calculated using measured boundary layer parameters and VFP simulated ones. These results indicate that boundary layer velocity profiles calculated with the new method using boundary layer parameters computed by VFP simulations are reasonably accurate for a high aspect-ratio and medium (or small) sweep angle wing, at subsonic airspeed under suitable flow conditions. A VFP simulation followed by calculation using the new boundary layer reconstruction method can be a rapid process for the reconstruction of boundary layer profiles. This process has finally been demonstrated on a blended wing body for the reconstruction of velocity profiles on its upper surface, where the boundary layer could be ingested by an engine intake.