A Numerical Analysis of Flow and Dispersion around a Cube

This work describes the computational fluid dynamic (CFD) simulation of flow and pollutant dispersion around a cube. The work attempts to model the characteristics of an atmospheric boundary layer type flow over a building which has a pollutant source at its roof centre. For the flow field, two different numerical schemes for the discretisation of convection have been employed namely the second order accurate QUICK scheme and the first order HYBRID-UPWIND scheme. The results for the velocity field appear to be inconclusive with reference to the merits of each of the schemes employed. Different regions of the flow appear to profit from the application of each scheme and, although the general flow field is reasonably well predicted, it is suggested that the inadequacies of the turbulence model employed may outweigh any benefits to be gained from the implementation of a higher order convection scheme. For the pollutant dispersion, variations in the turbulent Schmidt number in accordance with previously published work appear to improve the prediction of pollutant concentrations.