Experimental Analysis of TSTO Aerodynamic Interactions Based on Oil Flow Patterns at Hypersonic Speed

A small crack on body surface led to a tragic accident in 2003, which is the Columbia accident. During the shuttle’s re-entry, high temperature gas penetrated crack on leading-edge of the left wing and melted the aluminum structure, finally the Columbia blew up. Since early times, there are many fundamental studies about simple cavity-flow in hypersonic speed, and then, which becomes more active as a result of its disaster. In practical situation, no one can notify where the crack is formed during hypersonic flight, then worst of all, it may locates at most severe area such as Shock/Shock Interaction (SSI) and Shock/Boundary Layer Interaction (SBLI) point. In this study, pressure distributions and aerodynamic interaction flow-fields were investigated for No-Crack and With-Crack TSTO models at hypersonic speed (M∞=8.1). As a result, the flow-field around TSTO models was made clear, then the aerodynamic interaction flow-fields and the pressure distributions around crack are quite different between No-Crack and With-Crack TSTO at h/D=0.44. With-Crack TSTO produces a large separation region on the delta wing, which leads SSI in front of orbiter nose, and two peaks of pressure on the crack floor, which locates a reattachment point and a recompression region. These peak pressure values are almost the same as a value of the SBLI point in the case of No-Crack TSTO. Nomenclature D = diameter of orbiter, 23mm h = clearance between orbiter and booster L = chord length of booster, 200mm Λ = swept angle of booster, 75deg M = Mach number p = model surface pressure [Pa] T = temperature [K] Re = unit Reynolds number, 4.2×106 [m-1] x, y = coordinates [mm] φ = angle from orbiter nose in the symmetry plane d = length of square crack C = depth of square crack Subscripts 0 = stagnation point value ∞ = freestream value ref = reference value I