
Accession Number : ADA135152
Title : Final Report on Grant AFOSR820171.
Descriptive Note : Final rept. 1 May 8230 Apr 83,
Corporate Author : FLORIDA UNIV GAINESVILLE DEPT OF MATHEMATICS
Personal Author(s) : McKenna,P J
PDF Url : ADA135152
Report Date : 30 Jun 1983
Pagination or Media Count : 54
Abstract : During this period the principal investigator has considered the effect of the artificial far field boundary on a finite different approximation of the NavierStokes equations for a compressible fluid considered for two dimensional boundary conditions for the farfield boundary can results in some of the following phenomena: (1) reflecting boundary conditions, in which the disturbances in the physical variables represented by the difference between the steady state flow and the initial conditions are not allowed to exit through the farfield boundary but instead continue echoing up and down the grid; (2) underspecified boundary conditions, in which the converged steady state solution may depend on the initial conditions; and (3) overspecified boundary conditions in which large errors are introduced before convergence takes place. The following conclusions may be drawn from the numerical experiments conducted as a part of the research effort: There are four distinct artificial nonreflecting boundaries containing freestream information, these being the inflow, outflow, topsidewall and bottomsidewall. Each of these boundaries must be treated differentially, or errors are introduced into the system.
Descriptors : *Navier Stokes equations, *Compressible flow, *Fluid flow, *Numerical methods and procedures, Gas dynamics, Two dimensional flow, Far field, Boundaries, Linearity, Steady state, Nonlinear systems, Free stream, Flight simulation
Subject Categories : Numerical Mathematics
Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE