Fast Fluid Dynamics Simulation of the Airflow Around a Single Bluff Body

Fast and accurate simulation of the outdoor airflow distribution is important for studying urban microclimate. In this paper, two pressure-correction schemes (i.e., NIPC and NSPF) for solving the N-S equation item by item are implemented in OpenFOAM and their differences from the PISO algorithm in simulating the airflow around a single 1:1:2 bluff body are analyzed. The RNG k-ε turbulence model is chosen to study the airflow disturbance, while the second-order discretization scheme of Gauss limitedLinear is used to solve the advection term in the N-S equation. The results show that the NIPC can accurately predict the main airflow characteristics around the bluff body, while the NSPF cannot predict the recirculation region on its top. The two pressure-correction schemes underestimate the TKE distribution on the top and leeward sides of the bluff body when applying the RNG k-ε turbulence model, and the maximum relative error is about 30%. However, they are consistent with the results of the PISO algorithm under the same conditions. The two schemes are about 2.5-3.0 times faster than the PSIO algorithm when run on a CPU, and the NSPF is about 12% faster than the NIPC scheme.