Verification of Supersonic and Hypersonic Semi-Empirical Predictions using CFD

摘要

CFD was used to verify the accuracy of the axial force,normal force,and pitching moment predictions of two semi-empirical codes.This analysis consid- ered the flow around the forebody of four different aerodynamic shapes.These included geometries with equal-volume straight or tapered bodies,with either standard or double-angle nose cones.The flow was tested at freestream Mach numbers of M=1.5,4.0, and 7.0.The CFD results gave the expected flow pres- sure contours for each geometry.The geometries with straight bodies produced larger axial forces,smaller normal forces,and larger pitching moments compared to the geometries with tapered bodies.The double- angle nose cones introduced a shock into the flow,but affected the straight-body geometries more than the tapered-body geometries.Both semi-empirical codes predicted axial forces that were consistent with the CFD data.The agreement between the normal forces and pitching moments was not as good,particularly for the straight-body geometries.But even though the semi-empirical results were not exactly the same as the CFD data,the semi-empirical codes provided rough estimates of the aerodynamic parameters in a fraction of the time required to perform a CFD analysis.