Investigation of Shock Focusing in a Cavity with Incident Shock Diffracted by an Obstacle

Experiments and numerical simulations were carried out in order to investigate the focusing of a shock wave in a test section after the incident shock has been diffracted by an obstacle. A conventional shock tube was used to generate the planar shock. Incident shock Mach numbers of 1.4 and 2.1 were tested. A high-speed camera was employed to obtain schlieren photos of the flow field in the experiments. In the numerical simulations, a weighed essential non-oscillation (WENO) scheme of third-order accuracy supplemented with structured dynamic adaptive mesh adaptation was adopted to simulate the shock wave interaction. Good agreement between experiments and numerical results is observed. The configurations exhibit shock reflection phenomena, shock-vortex interaction and – in particular – shock focusing. The pressure history in the cavity apex was recorded and compared with the numerical results. A quantitative analysis of the numerically observed shock reflection configurations is also performed by employing a pseudo-steady shock transition boundary calculation technique. Regular reflection, single Mach reflection and transitional Mach reflection phenomena are observed and are found to correlate well with analytic predictions from shock reflection theory. This work has been supported by the Young Scientists Fund of the National Natural Science Foundation of China through Grant No. 51106178. ZHANG Qiang · CHEN Xin · HE Li-Ming · RONG Kang Aeronautics and Astronautics Engineering Institute of Air Force Engineering University, Xi’an, China CHEN Xin Collaborative Innovation Center of Advanced Aero-Engine, Beijing, China Ralf Deiterding Aerodynamics and Flight Mechanics Research Group, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom