Numerical investigations of shock-shock interaction in hypersonic flow.

摘要

Computational fluid dynamics (CFD) is now widely used as a tool for hypersonic flight simulation and vehicle design. In this dissertation, two-dimensional Euler and Navier-Stokes codes are used to numerically investigate several flow phenomena associated with the laminar hypersonic type IV shock-shock interaction problem. A MUSCL-type TVD scheme is employed in a beam-warming approximate factorization algorithm to solve the time-dependent equations implicitly. The codes provide the option to choose a perfect gas or an equilibrium air equation of state.; Type IV interaction for both the single and double incident shock cases are simulated in order to better understand the structure of the flow. Numerically obtained flow patterns, surface heat transfer rate, and surface pressure distributions are compared to experimental data. Generally good agreement is found in these comparisons. However, it has been found that one experimentally observed pattern in the double incident shock case actually exists only temporarily, and eventually transforms to another steady state pattern. Both a local numerical simulation and a full windtunnel numerical simulation support this conclusion.; The unsteadiness of the type IV interaction generated by a single incident shock is simulated and analyzed at a wide range of Mach numbers. The effect of Mach number and the assumption of chemical equilibrium have been addressed. A relationship between the fluctuation of the supersonic jet formed in this type of interaction and the bow shock motion is proposed. Compared to previous studies of this type, the more detailed observations made in the present study offer a better understanding of shock-on-shock interaction.