Prediction Accuracy of Non-Linear k–ε Models for Pollutant Dispersion around a Model Building

A numerical simulation was conducted to assess prediction accuracy of various non-linear models for estimating concentration field around a cubical model building with a stack vent located on its roof. The results of these models were compared with SKE model and wind-tunnel data. Three non-linear models, namely, Craft et al., Lien et al. and Rubinstein and Barton models were investigated where Craft et al. and Lien et al. models are cubic and Rubinstein and Barton model is quadratic. All the computations were performed by the use of the self-developed object-oriented C++ programming in OpenFOAM CFD package, which contains applications and utilities for finite volume solvers. Among the various models studied here, results of the SKE model for the concentration field were unfavorable, because it cannot reproduce the basic flow structure, such as the reverse flow on the roof. On the contrary, the non-linear models were able to predict the concentration field better than the SKE model due to inclusion of the quadratic and cubic terms. It can be said that concentrations predicted by all CFD models were less diffusive than those of the experiment, although the non-linear k–ε models have reduced this difference.

Keywords:

Pollutant dispersion , Numerical simulation , OpenFOAM , Non-linear k-ε models , Model building