Pressure gradient scaling method for fluid flow with nearly uniform pressure

Journal Article · Wed May 15 04:00:00 EDT 1985 · J. Comput. Phys.; (United States)

DOI:https://doi.org/10.1016/0021-9991(85)90168-8· OSTI ID:5544810

Ramshaw, J D; O'Rourke, P J; Stein, L R

A method is described for increasing the efficiency of numerical calculations of compressible fluid flow problems in which the pressure field is nearly uniform in space. This condition is ordinarily satisfied at low Mach number. It is shown that in such problems, the pressure gradient in the momentum equation may be multiplied by a scaling factor 1/..cap alpha../sup 2/ (..cap alpha..>1) without significant effect, provided that ..cap alpha.. is not too large and that the pressure inhomogeneities are not of interest. This scaling modification reduces the acoustic speed by a factor of ..cap alpha.., thereby increasing the effective Mach number by the same factor. This reduces the disparity between the acoustic and convective time scales, which improves the computational efficiency of many numerical schemes for compressible flow. The relation between the present approach and the ..cap alpha..-transformation of O'Rourke and Bracco is briefly discussed. The practical utility of the method is illustrated by sample calculations of combustion in ideal gas mixtures.

• Research Organization: Theoretical Division, University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5544810
• Journal Information: J. Comput. Phys.; (United States), Journal Name: J. Comput. Phys.; (United States) Vol. 58:3; ISSN JCTPA
• Country of Publication: United States
• Language: English

Related Subjects

640410* -- Fluid Physics-- General Fluid Dynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMICAL REACTIONS
COMBUSTION
COMPRESSIBLE FLOW
DISPERSIONS
FLAMES
FLUID FLOW
FLUIDS
GASES
MACH NUMBER
MIXTURES
NUMERICAL SOLUTION
OXIDATION
PRESSURE GRADIENTS
THERMOCHEMICAL PROCESSES
VELOCITY