Hypersonic Flow with Combined Leading-edge Bluntness and Boundary-layer Displacement Effect

A theoretical study is made of hypersonic flows over thin bodies subject to the combined effect of leading-edge bluntness^, boundary-layer displacement as well as surface incidence,, Within the scope of the boundary-layer theory and the hypersonic small-disturbance theorys an approach is developed based on a flow model consisting of three adjoining regionss an inner laminar boundary layerj an outer (detached) shock layers and between these two, a low-density entropy layer« This approach allows simultaneous treatment of the boundary layer and its outer inviscid flow field in a manner consistent with the Newtonian shock-layer approximation. The theory pertaining to the leading approximation for strong shock and -/—»»1 is completely developed and its simplicity permits solutions to a number of problems of interest. For the flat plate at zero incidences the theory yields a solution agreeing with the blast-wave theory at one limit and the strong inviscid-viscous interaction theory at the other. Results are also obtained for the flat plate at incidence. The results for the pure inviscid flows with tip-bluntness effect exhibit an oscillatory decay in pressure on slender cone and wedge afterbodies. This phenomenon signifies an idealized form of reimpingement of the shock layer on the afterbody at glancing incidence. Complementary to the aforementioned studys an examination is made of the similitude of hypersonic boundary layers, taking specifically the leading-edge bluntness into account. Rules for correlating pressures shock shape <, skin friction and heat-transfer rate are given. The simplification of these rules for flows with strong shock waves is pointed out.