Efficient Aerodynamic Analysis of Air-Breathing Hypersonic Vehicle using Local Surface Inclination Method based on Unstructured Meshes

An efficient aerodynamic analysis was conducted for rapid prediction of the aerodynamic performance of air-breathing hypersonic vehicles in the early design phase. Surface pressure calculation on compression surfaces was performed using local surface inclination methods such as modified Newtonian, tangent cone, and tangent wedge methods. The Prandtl–Meyer expansion method was adopted for surface pressure calculation on expansion surfaces. Sharma’s three-dimensional correction is applied to the Prandtl–Meyer expansion if needed. The reference temperature method was used for the prediction of the local skin friction coefficient. An efficient approximate streamline tracing method was suggested to calculate the reference length for each local surface cell with just one percent of the CPU time required for the original naive stream tracing method. An internal flow passage for air-breathing propulsion was also considered under the isentropic assumption for prediction of aerodynamic performance of a whole vehicle. Comparisons are made for aerodynamic coefficients calculated by the present code and a high fidelity CFD code for a X-51A-like configuration at flight conditions of Mach 5 and 6, and good agreements were obtained. The developed code is very efficient and possesses enough accuracy for engineering prediction of the aerodynamic performance of hypersonic air-breathing vehicles.