An efficient numerical approach for simulating airflows around an isolated building

Abstract

The efficiency and precision of numerical simulation are very important to study the airflow around buildings. A new simulating approach for predicting airflow around a building efficiently is proposed. The modeled turbulence kinetic energy is converted into resolved energy using the vortex method at the interface away from the inlet. This treatment helps to converge. A novel hybrid turbulence model, namely production-limited eddy simulation (PLES), works in the whole computational region. Then, the PLES model needs not treat the LES-RANS (large eddy-simulation-Reynolds-averaged Navier-Stokes) interface, making the computation running more easily. For testing the accuracy and efficiency of the PLES model, the WALE (wall-adapting local eddy-viscosity) model, an LES model, is applied to simulate the airflow around an isolated building on the same grid. And the effects of the underlying RANS models on the performance of the PLES models are investigated. The underlying RANS models are the BSL (baseline) k-ω and the SST (shear stress transport) k-ω models. The BSL PLES model obtains good predictions of the time-averaged streamwise velocity, but over-predicts the resolved turbulence kinetic energy (TKE) in comparison with the WALE model. The performance of the SST PLES model in predicting the time-averaged streamwise velocity is comparable to the WALE and the BSL PLES models. Furthermore, the SST PLES model gives better resolved TKE comparing with two other models. Meanwhile, the computing time needed in the new approach is 35% less than that needed in the LES computation.