Accession Number : ADP002946

Title :   Artificial Mass Concept and Transonic Viscous Flow Equation,

Corporate Author : TEXAS UNIV AT AUSTIN DEPT OF AEROSPACE ENGINEERING AND ENGINEERING MECHANICS

Personal Author(s) : Dulikravich,G. S. ; Niederdrenk,P.

Report Date : FEB 1984

Pagination or Media Count : 10

Abstract : By varying the grid clustering on the surface of an airfoil, it was observed that symmetric shocked solutions develop with a nonunique shock strength and location when numerically solving the full potential equation. It is shown analytically that the conventional form of artificial density (or viscosity) produces a number of truly nonlinear terms which are suspected to be the cause of the nonuniqueness for all the finite grid sizes. A concept of artificial mass flow is shown to be suitable for analytically evaluating a new exact form of the switching function that eliminates all the nonlinear terms for any value of the local Mach number. The resulting expanded full potential equation then becomes a third order partial differential equation of permanently parabolic type resembling Sichel's transonic viscous flow equation. Consequently, our expanded full potential equation does not require the introduction of the customarily-used artificial time concept. (Author)

Descriptors :   *Transonic flow, *Viscous flow, Mathematical models, Potential flow, Partial differential equations, Airfoils, Shock, Mass, Numerical methods and procedures, Taylors series, Mass flow, Grids, Clustering, West Germany

Distribution Statement : APPROVED FOR PUBLIC RELEASE