Continuity of Lifting Surface Theory in Subsonic and Supersonic Flow

The continuity of linear theory for lifting surfaces in subsonic and supersonic e ow is discussed. The unsteady pressure kernel functions of the singular integral equation are summarized for all Mach numbers in the Laplace transform domain. The sonic kernel in the steady e ow is obtained as a e nite limit from both the subsonic and supersonic sides when the Mach number tends to unity. Numerical examples are given using the doublet-point method with three different kernel functions, showing continuous results through the unit Mach number. The results also show how a rectangular wing with various Mach numbers approaches to the two-dimensional airfoil as the aspect ratio increases.