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Mekkes, Gregory L.

Publications and source records attributed to Mekkes, Gregory L..

Fuel Plume Image Mixing Analysis Formulation With Proper Treatment of Non-Constant Velocity Flowfields

A previously developed technique allows an estimate of integral mixing to be obtained from an image of laser scattered light from particle seeded fuel in the hypervelocity flow through a scramjet combustor. This previous mixing analysis formulation contains an assumption of a constant velocity flowfield across the plane of the fuel plume image. For high-speed scramjet combustors, the velocity flowfield is quite uniform and an assumption of constant velocity works well. Applying this same mixing analysis technique to fuel plume images obtained from a mid-speed scramjet combustor makes it desirable to remove the constant velocity assumption. This is due to the non-uniform velocity flowfields present in mid-speed scramjet combustors. A new formulation of the mixing analysis methodology is developed and presented so that the technique can be applied to a mid-speed scramjet combustor without the need to assume a constant velocity flowfield.

Mekkes, Gregory L.↗

Computational analysis of hypersonic shock wave/wall jet interaction

The purpose of this study is to investigate the CFD code General Aerodynamic Simulation Program (GASP) for application to a specific scramjet combustor phenomenon, that of an adverse pressure gradient caused by an oblique shock wave impinging upon a wall cooling film. The basis of this investigation is data available from an existing experimental study, which includes wall pressure, wall heat transfer, and schlieren photographs. This experimental study was conducted at a nominal Mach number of 6.0 in the Calspan 48-inch shock tunnel. The particular case of interest generates flow separation at the shock impingement point. Two algebraic turbulence models, the Baldwin-Lomax model and the Goldberg model, are considered for this computational study. Resultant computational wall pressure and heat transfer for both turbulence models are compared with experimental data. The Goldberg turbulence model provides a more accurate prediction of the recirculation region, and as a result, a better comparison with the experimental data.

Mekkes, Gregory L.↗