Abstract: An inverse trapezia vortex generator based on a previous investigation of the full ramp is designed to shorten the isolator. The vortex generator is placed on the lower wall at the isolator entrance. Computational fluid dynamics simulations are performed on the isolator. Numerical results indicate that for the same backpressure the overall length of the isolator can be reduced by 40% with the introduction of the inverse trapezia vortex generator. Compared with the full ramp, the truncated length is improved by approximately 5%. The length of the shock train does not change lineally with the change of the swept angle. With the optimum swept angle design, the length of the shock train can be kept at the minimum, and the total pressure recovery coefficient in the isolator with an inverse trapezia vortex generator is at the same level as that of the full ramp.

Key words: scramjet, isolator, shock train, inverse trapezia vortex generator, numerical simulation