Aerodynamic Characteristics of a Lifting-Body-Type Reentry Vehicle at Transonic Speeds

A flowfield investigation of a lifting-body-type reentry vehicle at transonic speed by pressure-sensitive paint measurement has been conducted. The purpose of this study is to investigate two different flowfields for baseline and upswept upper-aft body configurations of the vehicle by detailed surface pressure measurement, which nonlinear lift characteristics around angle of attack of 5 deg at transonic speeds were found for the baseline configuration while the configuration with upswept upper-aft body had nearly linear lift characteristics in the former researches. As a result, it is found that the nonlinear lift characteristic of the baseline configuration is caused by a qualitative change of flow pattern on the upper-aft body near fin and inboard surface of the fin, where the expansion wave generates the lift at the angle of attack 0 deg while the flow in the same region loses the lift at the angles of attack 5 − 15 deg due to the boundary layer separation. On the other hand, unlike the baseline configuration, it is observed for the configuration with upswept upper-aft body that the flowfield on the same region shows no flow pattern change with the change of angle of attack, leading to the nearly linear lift characteristics.