Acoustical Methods in Supersonic Aerodynamics

The paper illustrates certain techniques common to acoustics and supersonic aerodynamics. The basic equations describing hydrodynamical phenomena taking place in a supersonic, inviscid stream are developed. After linearization, the equations are solved for the velocity potential resulting from an arbitrary source distribution in the plane z − 0. The integration of the results for two-dimensional flow is carried out, and the application to various aerodynamic problems is cited. As a second illustration, an analogy, attributable to von Kármán, between two-dimensional flow caused by a distribution of acoustic oscillators along a line having arbitrary time histories and the steady three-dimensional flow about a thin wing is described. Using the techniques of Fourier integrals, this analogy is used to compute the wave drag caused by a symmetrical wing at zero lift.