Accession Number : ADA296514

Title :   Pressure Updating Methods for the Steady-State Fluid Equations.

Descriptive Note : Contractor rept.,

Corporate Author : INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

Personal Author(s) : Fiterman, A. ; Turkel, E. ; Vatsa, V.

PDF Url : ADA296514

Report Date : MAY 1995

Pagination or Media Count : 16

Abstract : We consider the steady state equations for a compressible fluid. Since we wish to solve for a range of speeds we must consider the equations in conservation form. For transonic speeds these equations are of mixed type. Hence, the usual approach is to add time derivatives to the steady state equations and then march these equations in time. One then adds a time derivative of the density to the continuity equation, a derivative of the momentum to the momentum equation and a derivative of the total energy to the energy equation. This choice is dictated by the time consistent equations. However, since we are only interested in the steady state this is not necessary. Thus we shall consider the possibility of adding a time derivative of the pressure to the continuity equation and similar modifications for the energy equation. This can then be generalized to adding combinations of time derivatives to each equation since these vanish in the steady state. When using acceleration techniques such as residual smoothing, multigrid, etc. these are applied to the pressure rather than the density. Hence, the code duplicates the behavior of the incompressible equations for low speeds. (AN)

Descriptors :   *STEADY STATE, *COMPRESSIBLE FLOW, *EULER EQUATIONS, VELOCITY, MATHEMATICAL MODELS, ALGORITHMS, LINEAR SYSTEMS, TIME DEPENDENCE, ENERGY, GRIDS, PRESSURE, CONVERGENCE, MACH NUMBER, LIFT, INVISCID FLOW, VISCOUS FLOW, VISCOSITY, MOMENTUM, RUNGE KUTTA METHOD, EQUATIONS OF STATE, INCOMPRESSIBILITY, TRANSONIC FLOW.

Subject Categories : Operations Research
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE