A comparison of predicted and measured aeroheating on a reentry vehicle flap geometry

The purpose of this paper is to illustrate the applicability of two different techniques for predicting flap heating, and to compare the results of these techniques with wind tunnel data obtained on a flap model. The wind tunnel data was obtained in the Naval Surface Weapons Center's Tunnel 9 using an RV model equipped with six drag flaps. One flap and the RV surface surrounding the flap were instrumented with heat transfer gages to measure the heating distributions on the flap surface and side walls and on the surrounding RV surface. The two analytical techniques are related in that they both use an inviscid/boundary layer solution technique to predict aeroheating. The first and less sophisticated of these two techniques uses an inviscid/boundary layer program to predict the heating on the RV surface, as well as the Mach number distribution through the boundary layer and the rotational inviscid layer just upstream of the flap. The technique of Cassel and Jarrett, which makes use of two dimensional oblique shock wave relations, is then used with the predicted upstream Mach number distribution to predict the heating distribution on the flap surface and side walls. The second technique used to predict the flap heatingmore » uses an inviscid and boundary layer approach in which the complete RV and flap geometry is modeled. This technique is significantly more complicated than the first technique, and is capable of modeling the three dimensional aspects of the flowfield in the region of the flap. Thus this approach should produce significantly more accurate solutions than the technique of Cassel and Jarrett which is essentially two dimensional in nature.« less