Simulation of pollution dispersion behind a building using a RANS-LES model

Today the air pollution is one of the biggest problem specially in mega cities and it effects directly on human health and environment. in this article pollution dispersion for the light gas pollutant around a building in turbulent 3D incompressible flow using a hybrid turbulence model has been investigated. Pollution around a building in low speed wind may aggregate in some regions and make special problems for pedestrian and environment. Turbulent wind flow over buildings due to the complexity like sharp corners, ground effect, different vortexes and other factors is one of the best choices to evaluate efficiency and accuracy of turbulence methods. DES is hybrid RANS-LES models for simulating turbulent flow which for their characteristic, treat near wall as RANS and farther the wall act as LES model. Consequently computational time will decrease compared to traditional LES models. To evaluate DES model, DES results has been compared with smagorinsky and one-equation model. Also to validate, the simulation results are compared with experimental data. The DES results show good agreement with experiment and LES models and this hybrid model has a good potential for large scale wind engineering problems.