Coupling of WRF and building-resolving urban CFD models for analysis of strong winds over an urban area

Nakayama, Hiromasa   ; Takemi, Tetsuya*; Nagai, Haruyasu  

Coupling of the NWP (Numerical Weather Prediction) model with the CFD (Computational Fluid Dynamics) model using LES (Large-Eddy Simulation) can be effective means to predict small-scale wind fluctuations over urban areas under real meteorological conditions. In this study, we performed a numerical simulation for strong winds over the central Tokyo during the passage of Typhoon Melor (2009). In the LES model, the urban surface geometry is explicitly resolved. At the inlet boundary of the LES computational region, the wind profile obtained from the NWP model is imposed and turbulent fluctuations are generated by the existing turbulent inflow generation method (Kataoka et al, 2002). Compared to Mesoscale Analysis data by Japan Meteorological Agency (JMA), the simulation results show that the variability of wind velocity is similar to that observed at a surface site of JMA.