Evaluation of Two Different k-e-vv-f Turbulence Models for Natural Convection in a Rectangular Cavity

摘要

A numerical study of natural convection in a rectangular cavity with the k-e-vv-f models is presented. The primary emphasis of the study is placed on the investigation of accuracy and numerical stability of the k-e-vv-f models for a natural convection problem. Both the original vv-f model (1) and its modified one (2) are considered. Both models are applied to the prediction of natural convection in a rectangular cavity together with the two-layer model (3). The original model exhibits the numerical stiffness problem when used with the segregate solution procedure like the SIMPLE algorithm and a simple remedy for this problem is proposed. The computed results are compared with the experimental data commonly used for validation of the turbulence models. It is shown that the original vv-f model predicts accurately the mean velocity, velocity fluctuation, Reynolds shear stress, turbulent heat flux and the local Nusselt number at the hot wall. The modified vv-f model predicts well all the quantities, but the accuracy of solution is a little deteriorated than that of the original model. The two-layer model predicts poorly the mean vertical velocity component and underpredicts the turbulent quantities. As is already known in the literature, the modified vv-f model enhances greatly the numerical stiffness problem of the original model.