Experimental and Computational Investigation of a Dynamic Starting Method for Supersonic/Hypersonic Inlets

This paper presents the current results of experime ntal and numerical studies of a dynamic door starting method applied to a nominally two-dimensional scramjet inlet with variable contraction ratio (CR). The inlet was test ed in a Mach 4 wind tunnel with average Reynolds number of 5.77e+7 per meter, and a broad range of door rotation rates were investigated. The use of a non-ejectable, rotating inlet cover was found to improve the starting limit of overcontracted inlets by approxim ately 10%, which yielded an improvement of inlet pressure ratio of 58%. The numerical flow solver used to model each cont raction ratio was GASP v. 4.2 which uses a RANS formulation. A Roe flux-difference splitting scheme with min-mod limiting was chosen to compute the inviscid fluxes due to its strength in resolving discontinuities. The Wilcox k-ω (1998) turbulence model was used for viscous solutions and a dual-time stepping Euler implicit a lgorithm was used for time accurate predictions. Numerical results coincided well with experimental pressure measurements and shock patterns obtained from schlieren photography.