On the computation of near wake, aerobrake flowfields

Simulations of the near wake flowfield behind three aerobrakes have been implemented with Program LAURA, an algorithm for obtaining the numerical solution to the governing equations for three-dimensional, viscous, hypersonic flows in chemical and thermal nonequilibrium. Emphasis is placed on understanding the conditons which are likely to cause the shear layer to impinge on a payload positioned behind the aerobrake. A linear relationship between shear layer deflection angle and angle of attack (or lift-to-drag ratio) has been identified in several ground based tests. A similar relation appears in the numerical simulations, though there is some evidence that deflection angels may increase somewhat due to the effects of gas chemistry. Shear layer impingement can raise local heating levels a factor of 10 higher than levels present without impingement. Payload heating levels near impingement points are a larger percentage of stagnation point heating levels at higher altitudes and peak payload heating levels are likely to occur earlier in the trajectory than peak heating on the forebody stagnation point.