Mathematical description of turbulent flows

Journal Article · Sun Aug 01 04:00:00 EDT 1982 · J. Hydraul. Div., Am. Soc. Civ. Eng.; (United States)

OSTI ID:5859295

Findikakis, A N; Street, R L

The mathematical description of uniform density and thermally stratified flows in terms of space averages is reviewed. The governing equations are presented and the use of alternative space filters is discussed. Different models for Sub-Grid-Scale (SGS) turbulent transport are examined. A simple algebraic model for the SGS Reynolds stresses and turbulent heat fluxes in thermally stratified flows is presented. The model is cast in eddy viscosityeddy diffusivity form. Its derivation is based on making appropriate closure approximations in the differential equations for the Reynolds stresses and the turbulent heat fluxes and introducing simplifying assumptions to reduce these equations to a system of algebraic equations. The solution of this system yields eddy coefficients which are functions of a local SGS turbulence length scale and the local structure of the velocity and the temperature fields. The variation of these coefficients with a local Richardson number is examined. Potential numerical problems which can be caused by improper formulation of the model are examined.

• Research Organization: Hydr./Hydrology Grp., Bechtel Civ. and Minerals Inc., P.O. Box 3965, San Francisco, Calif. 94119; Dept. of Civ. Engrg., Stanford Univ.
• OSTI ID: 5859295
• Journal Information: J. Hydraul. Div., Am. Soc. Civ. Eng.; (United States), Journal Name: J. Hydraul. Div., Am. Soc. Civ. Eng.; (United States) Vol. 108:HY8; ISSN JYCEA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
DENSITY
DIFFERENTIAL EQUATIONS
EQUATIONS
FILTERS
FLUID FLOW
HEAT FLUX
MATHEMATICAL MODELS
PHYSICAL PROPERTIES
REYNOLDS NUMBER
RICHARDSON NUMBER
SPACE DEPENDENCE
STRESSES
TEMPERATURE DISTRIBUTION
TURBULENT FLOW
VELOCITY