Modifications to Reynolds-averaged Navier–Stokes turbulence models for the wind flow over buildings

Abstract

The standard k–ε turbulence model is well known to perform poorly in the stagnation regions in front of buildings where it over-predicts the turbulent kinetic energy, k. It is less well known that this error is compounded by an excess decay of the turbulence over and behind a building so that k is eventually under-estimated in the building wake. A new formulation of the eddy viscosity in the standard k–ε turbulence model was developed and compared with previous modifications designed for stagnation regions. The new formulation provides more accurate values of k and it showed similar results for streamwise mean velocity predicted by the shear stress transport turbulence model. A blend between the new model and the standard eddy viscosity model provides the best overall prediction of the mean velocities and turbulence.

Keywords

• wind resource assessment
• stagnation point anomaly
• computational fluid dynamics
• eddy viscosity
• rans turbulence models