Accession Number : AD0710839

Title :   BILDUNG SCHWACHER STATIONAERER STOBWELLEN IN RELAXIERENDEN GASGEMISCHEN (Formation of Weak, Stationary Shockwaves in a Mixture of Relaxing Gases),

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

Personal Author(s) : Romberg,Guenter

Report Date : 07 NOV 1969

Pagination or Media Count : 13

Abstract : The formation of a fully dispersed shock wave in a binary mixture of relaxing gases is investigated. It is assumed that the gas is bounded by a piston at the left, and at time t = 0 is in static thermodynamic equilibrium. The piston velocity changes from zero at t = 0 to a constant non-zero value at t > 0. A uniformly valid approximation for the resulting wave motion is found by the method of matched asymptotic expansions. It turns out that the formation of a steady shock wave depends on the temperature dependence of the vibrational specific heats. If the coefficient omega of the non-linear term in Burgers equation is greater than zero, a steady shock wave is formed. However, for omega or = 0 this is not the case. One finds that the cases omega or = 0 are not realized in nature. Numerical results for the shock formation in relaxing air indicate, how the accuracy of acoustic theory decreases due to non-linear effects as time proceeds. (Author)

Descriptors :   (*SHOCK WAVES, PRODUCTION), RELAXATION TIME, GAS FLOW, PISTONS, THERMODYNAMICS, NUMERICAL ANALYSIS, WEST GERMANY

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE