Accession Number:

ADA243709

Title:

Effective Viscosity in the Simulation of Spatially Evolving Shear Flows with Monotonic FCT Models

Descriptive Note:

Memorandum rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

Report Date:

1991-12-13

Pagination or Media Count:

37.0

Abstract:

The global numerical diffusion of a model for the low-Mach-number simulation of free mixing layers is investigated. The numerical model solve the inviscid time-dependent conversation equations for mass, momentum and energy, for ideal gases. The equations are solved using an explicit Flux-Corrected Transport FCT algorithm, directional timestep-splitting techniques on structured grids, and appropriate inflow and outflow boundary conditions. Effective measurement of the numerical diffusion of the model in uniform grids is performed by comparison of the laminar spread of the simulated mixing layers with that predicted by boundary layer theory. The results show that the residual numerical diffusion of the FCT model can emulate physical viscosity for laminar shear flows at moderately high Reynolds numbers. The global numerical diffusion is not very sensitive to changes in free-stream velocity ratio, and can be reduced in a predictable way be refining the grid spacing.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE