Numerical/experimental investigation of 3-D swept fin shock interactions

Three-dimensional forward swept fin shock-shock interactions are examined using laminar computational fluid dynamics. The results are compared to schlieren images and stagnation line heat flux data on a 0.5 inch diameter cylindrical edge fin previously published by Berry and Nowak. The cases investigated include Type III and Type IV shock interactions, with a high localized heat flux due to jet or shear layer impingement. Numerical results are presented for three shock-on-fin interactions with a fin leading edge sweep of zero (perpendicular to the freestream), 15°, and 25°. Results indicate that when the supersonic jet impinges on the body the resulting flow is unsteady due to vortex motion in the impingement region. The predicted peak in surface heat flux for the 15° forward swept case is very narrow, and is higher than the experimental data. The predicted peak for the 25° forward swept case is wider, and is lower than the experiment. Off-axis heat flux was not measured experimentally, but the computations show that circumferential heat flux gradients are an order of magnitude smaller than longitudinal. The peak heat flux falls by only 5% in the first 11.5° around the fin, indicating that off-axis heating is an important design consideration in these interactions.