Accession Number : ADA299639

Title :   3D Vector Wavelet-Based Subgrid Scale Model for LES of Nonequilibrium Turbulence.

Descriptive Note : Performance rept. 21 Feb 94-20 Feb 95,

Corporate Author : HOUSTON UNIV TX

Personal Author(s) : Zimin, Valery ; Hussain, Fazle

PDF Url : ADA299639

Report Date : 11 APR 1995

Pagination or Media Count : 33

Abstract : We have laid the foundation to develop and validate LES using wavelets as a functional basis and based on subgrid scale (SGS) modeling using vector wavelets. Wavelet LES (WLES) consists of subgridscale model equations (SSM) and space-resolved model (SRM) equations. Using a vector wavelet decomposition of the velocity field a simple model for locally isotropic turbulence has been derived from the Navier-Stokes equation. This model, which involves no empirical or adhoc parameter Incorporates nonlocal inter-scale interactions, reveals backscatter and can be applied to represent small-scale turbulence in LES schemes. Stationary solutions of the model equation & produce the Kolmogorov k(5/3) inertial spectrum and the k(4) infra-red spectrum. We have completed derivation of the SRM equations based on the helical wave decomposition. We will test the SRM equations using the computational resources in this NAS operational year. A wavelet-based subgrid-scale model (WSSM) will be generalized to account for anisotropic and inhomogeneous turbulence in wall-bounded flows and will employ a nonuniform grid to resolve the near-wall structures. (AN)

Descriptors :   *MATHEMATICAL MODELS, *TURBULENCE, *NONEQUILIBRIUM FLOW, VELOCITY, COMPUTERIZED SIMULATION, GRIDS, EDDIES(FLUID MECHANICS), TURBULENT BOUNDARY LAYER, ENERGY TRANSFER, BACKSCATTERING, COMPUTATIONAL FLUID DYNAMICS, THREE DIMENSIONAL, FLOW FIELDS, APPROXIMATION(MATHEMATICS), KINETIC ENERGY, NAVIER STOKES EQUATIONS, VISCOSITY, INFRARED SPECTRA, SKIN FRICTION, BOUNDARY LAYER FLOW, NONUNIFORM.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE