Design Optimization of a Novel Flush Boundary Layer Diverter

A novel boundary layer diverter is designed and optimized for increasing the performance of a typical semi-submerged inlet ingesting large amounts of boundary layer flow. A conceptual diverter configuration based on the prior optimization study is first parametrized with seven design variables. A response surface model is constructed for the pressure recovery at the aerodynamic interface plane (AIP). The flow fields over the diverter and through the inlet duct are computed with SU2 and a baseline diverter is constructed from the response surface model for maximum pressure recovery. The baseline diverter is then placed in a free-form deformation box and shape optimized using the adjoint solver of SU2 with hundreds of design parameters. The optimum configuration provides 2.4% and 7.93% increase in the pressure recovery and the mass flow rate, respectively, together with a significant reduction in flow distortion. The novel diverter is then shape optimized together with the inlet duct. Together with all the performance parameters, the pressure recovery is improved by more than 3%. It is shown that the novel boundary layer diverter by being flush to the inlet surface induces a much smaller drag compared to the conventional diverters.