SOME SIGNIFICANT DEVELOPMENTS IN AERODYNAMICS SINCE 1946: DANIEL AND FLORENCE GUGGENHEIM MEMORIAL LECTURE

Abstract

This chapter discusses some significant developments in aerodynamics since 1946. Concerning wing theory, A. Pucket applied the method of singularities into the first theory of supersonic flow around axisymmetric bodies. Supersonic sources distributed along the axis of the body were used. H. S. Tsien introduced doublets to include in the theory the lift for the case of a body of revolution with angle of attack. These supersonic sources and doublets are arranged in such a way that their effect is restricted to the interior of a Mach cone, the apex of which is the point of singularity. Thus, the solution is essentially identical with the solution of a time-dependent two-dimensional acoustic problem, where the length-co-ordinate in the flow direction replaces the time-co-ordinate of the acoustic phenomena. The chapter also discusses interference effects between the wing and the body structures of the airplane that are necessary to carry payload, passengers, or fuel. The most significant example of favorable interference is the arrangement popularly known as the area rule. W. Hayes has shown in his doctoral dissertation at the California Institute of Technology that the resulting flow around a system consisting of long bodies and a low-aspect ratio wing, at large distances, can be represented as originating from singularities distributed along the axis. Hence, the drag can be considered as caused by a single equivalent body of revolution.