Comparison of Field Measurements and Numerical Simulations for Atmospheric Boundary Layer Flow over a Cylindrical Building

• Main Authors: Bo-WeiChen, 陳柏維
• Other Authors: Yu-Ting Wu
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/h8qnk4

碩士 === 國立成功大學 === 工程科學系 === 105 === In this study, we carried out a field measurement and Fluent simulations to investigate the interaction between atmospheric boundary layer flow and the wake produced from a tall cylindrical building named Tainan FE21. In the field measurement, a profiling Doppler wind LiDAR, WindCube@V2 offshore, was used to measure the wake produced from the building. In the case study, the details of the building and the LiDAR specifications will be presented. Turbulence statistics of the wind data measured from the LiDAR include time-averaged horizontal wind velocity, vertical velocity gradient, turbulence intensity, and vertical momentum flux. The power spectrum analysis was carried out using the method of fast Fourier transform (FFT) to support the reliability of the wind data measured from the LiDAR. In the Fluent simulations, the Navier-Stokes (N-S) equations of unsteady turbulent flow were solved using the Large Eddy Simulation technique in which the Wall-Adapting Local Eddy-Viscosity (WALE) model with a constant WALE coefficient is used to parameterize the subgrid-scale (SGS) stress. The hexahedral meshes are set up in the entire computational domain with a total number of approximately 2.28 million. Based on the analysis of the LiDAR measurements, two inflow conditions were observed and used to perform two Fluent simulations, which are named Case A and Case B. The comparison of the results between the field measurement and the Fluent simulations shows better agreement in the Case B study. From this comparison, we can conclude that the inflow conditions used in the Fluent simulations have great influence on the simulation results. The inflow condition which has smaller standard deviation and is parallel to a line crossing the building position and the LIDAR deployment position will present better agreement for the comparison of the results between the field measurement and the Fluent simulations.