Accession Number : AD0718181

Title :   Comparison of Several Mixing Length Models for Turbulent Boundary-Layer Computations.

Descriptive Note : Aeronautical rept.,

Corporate Author : NATIONAL AERONAUTICAL ESTABLISHMENT OTTAWA (ONTARIO)

Personal Author(s) : Chan,Y. Y.

Report Date : MAR 1970

Pagination or Media Count : 52

Abstract : A computational method for turbulent boundary layers in an incompressible two-dimensional flow was formulated. The governing differential equations for the mean flow are solved by an implicit finite differential equations for the mean flow are solved by an implicit finite difference method. The Reynolds shear stress is correlated by Prandtl's mixing length concept. Four models of correlation for the mixing length are studied and prediction based on these models is assessed by comparison with several sets of experimental data. It is found that models correlated only to local mean flow cannot adjust themselves to the proper turbulent state for highly non-equilibrium flow. If the turbulent state is considered explicitly by computing the mixing length from the turbulent energy equation, the results show excellent agreement with experimental data. This model is thus recommended for practical uses. (Author)

Descriptors :   (*TURBULENT BOUNDARY LAYER, MATHEMATICAL ANALYSIS), MATHEMATICAL MODELS, TWO DIMENSIONAL FLOW, INCOMPRESSIBLE FLOW, REYNOLDS NUMBER, SHEAR STRESSES, CORRELATION TECHNIQUES, CANADA

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE