A new zero-equation turbulence model for micro-scale climate simulation

Micro-scale climate is vital for the health and comfort of residents in urban areas. Simulation platforms being used to predict micro-scale climate usually take CFD (Computational Fluid Dynamics) as their core procedure. The popular turbulence models in practical CFD application for micro-scale climate are the k-ɛ series models. Given that the two-equation models might cost too much CPU time, they can hardly be applied at the design stage of complex urban area. Compared with the two-equation models, zero-equation turbulence models can reduce the computer load significantly. This paper proposes a new two-layer zero-equation turbulence model specific for the micro-scale climate simulations. The model assumes the turbulence viscosity as a function of velocity deformation rate and the length scale in the inner layer and function of length scale and local mean velocity in the outer layer. Validated with the wind-tunnel experiment data, this new zero-equation turbulence model can give reasonably acceptable results in micro-scale climate simulations. Besides, it costs much less CPU time and computer memory than the standard k-ɛ model does. This new zero-equation turbulence model can be an applicable alternative in micro-scale climate research.