Ensemble simulation for micro-meteorological wind condition using locally-mesh refined lattice Boltzmann method

Hasegawa, Yuta   ; Onodera, Naoyuki   ; Idomura, Yasuhiro   

A wind simulation code "CityLBM" has been developed for the prediction of plume dispersion in urban areas. CityLBM utilizes a locally mesh-refined lattice Boltzmann method, where turbulent winds near the ground is captured by refining the mesh on low altitude region, and be able to perform real-time wind simulations with a meter-resolution using GPU-accelerated systems. In this study, we validated an ensemble simulation against the field experiment in Oklahoma City (JU2003) with the 100 ensemble members, computational region of 4096 m 4096 m (horizontal) 2560 m (vertical) and the mesh resolution of 4 m near the ground and buildings. In the comparison between the ensemble simulation and the field experiment, wind speed showed good agreements within the range of 1 (where is variance of ensemble simulation), and the average value of the tracer gas concentration satisfied the factor2 agreements.