Author(s): Catherine Villaret

Linked Author(s):

Keywords: No Keywords

Abstract: Many turbulence models can be found in the litterature as reviewed,for example,in Rodi(1980)In the first-order closure models,all double-order correlations are directly related to the meanflow gradients through an eddy viscosity coefficient.This method,which is computationalyadvantageous,does not yield any insight into the turbulent structure and is only justified whensufficient data are available to validate the model coefficients.Second-order closure models,which solve a set of transport equations for all double-order correlations,incorporate morephysical processes than thefirst-order closure models.These equations,which are derived asan exact form from the Navier-Stokes equations,introduce some higher-order correlation termswhich have to be modeled in terms of the unknown double-order correlations and mean flowgradients as a function of the turbulent velocity q(q²=u²))and turbulence length scale A.Inorder to close the system,transport equations for q"A"have been derived.For example,thismethod(with m=3,n=-1)has been used in the popular k-e model,which carries twodynamic equations for the turbulence kinetic energy k(k=q²/2)and turbulence dissipation c.

DOI:

Year: 1989