Study on head configurations increasing aerodynamic rolling stability of ground-based hypersonic testing system

Rocket sled testing is a typical high speed, high dynamic and high credibility ground-based high-speed testing technique, which has the ability to simulate the actual operating conditions. The monorail rocket sled is a better choice of the ground-based hypersonic testing system, as its light-weighted and low drag force characteristics. However, the rolling of the rocket sled caused by the impact load is unavoidable in high-speed situation, and the unstable rolling of the rocket sled would cause the severe damage. To prevent the unstable rolling of the monorail rocket sled, this study firstly studied the flow mechanism causing the static rolling stability of a quasi-hypersonic rocket sled using computational fluid dynamics which is that two unsymmetrical quasi-convergent flow channels were formed and cause the velocity and pressure difference on the two sides of the rocket sled. The restoring rolling moment will be introduced by the pressure difference, which is proportional to the rolling angle causing the static rolling stability. Secondly, two designing concepts were promoted from this flow mechanism to increase the static rolling stability including expanding the operating area of the quasi-convergent flow pipe as well as designing secondary quasi-convergent flow pipe. Finally, two configurations named stability-enhancing rudder and quasi-wing were designed in this paper referring to the above designing concepts. 40% rolling stability incensement was reached by stability-enhancing rudder, while 91% was achieved by quasi-wing.