Pressure distribution on two wings with curved leading edges at supersonic speeds

Abstract

Results are presented of a study of the pressures on the flat windward surfaces of two wings with curved, sharp leading edges. The leading edges of one of the wings are convex outwards, whereas those of the second are concave outwards. The wings were tested at nominal free stream Mach numbers of 2.5, 3.5 and 4.5. The results indicate that the changes in flow development due to the curvature of the leading edges are qualitatively similar at all the Mach numbers. In the case of the first wing, the spanwise pressure distribution changed considerably as the flow developed downstream of the vertex. However, the changes in the spanwise pressure distribution on the wing with concave leading edge, though observable, were much less. The pressure distribution on the two wings has been calculated using the concept of an 'equivalent delta wing', but modified to take into account the upstream effect. Comparisons with experiments show that the agreement is fairly good, except at very high incidences and over the outer half of the semi-span. Possible reasons for this discrepancy are discussed. Finally an attempt has been made to justify the definition of an equivalent delta wing based on a simple physical idea.