Accession Number : AD0710835

Title :   UEBER DIE ANWENDBARKEIT DES ANALYTISCHEN CHARAKTERISTIKENVERFAHRENS BEI WELLENAUSBREITUNGEN IN RELAXIERENDEN GASEN (On the Application of the Analytic Method of Characteristics to Wave Propagation in a Relaxing Gas),

Corporate Author : DEUTSCHE FORSCHUNGS- UND VERSUCHSANSTALT FUER LUFT- UND RAUMFAHRT E V AACHEN (WEST GERMANY)

Personal Author(s) : Romberg,Guenter

Report Date : 12 SEP 1969

Pagination or Media Count : 6

Abstract : In two recent studies J. F. Clarke and W. Lick independently used an analytic method of characteristics to investigate plane waves propagating in a relaxing gas. It turns out that their technique fails to produce a uniformly valid first order solution. The present paper is concerned only with the wave problem studied by Lick, i. e. the formation of a weak steady shock wave by a piston. One finds that in case of a relaxing gas the analytic method of characteristics leads to nonlinear differential equations in a first approximation, if this approximation is to be uniformly valid. If the nonlinear terms are disregarded, a uniformly valid first approximation cannot be achieved, no matter how the coordinates in the physical plane are chosen. The well-known hypothesis due to G. B. Witham ('linearized theory gives a valid first approximation to the flow everywhere provided that in it the approximate characteristics are replaced by the exact ones') fails in case of a relaxing gas. (Author)

Descriptors :   (*SHOCK WAVES, PROPAGATION), DIFFERENTIAL EQUATIONS, APPROXIMATION(MATHEMATICS), WEST GERMANY

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE