Computational Investigation of Supersonic Impinging Jet Using PAK-3D Code

The results of an experimental and computational study of a moderately under expanded axisymmetric supersonic jet issuing from a converging nozzle and impinging on a ground plane are presented. The goal of this work is to develop a better understanding of impinging jet flow field. Comparisons of computational results using PAK-3D with published results reveal that the code has captured the significant features of this complex flow and were in remarkably good agreement with the published data for the primary test case. The experiments and computations both revealed the presence of the impingement zone stagnation bubble, which contains low velocity re-circulating flow. Other features, including the complex shock structure and the high speed radial wall jet, were also found to be very similar. The ability to measure and predict accurately the impinging jet behavior, especially near the ground plane, is critical because these are regions with very high mean shear, thermal loads, and unsteady pressure forces, which contribute directly to the problem of ground erosion in STOVL applications. (author)