Large eddy simulation of wind field analysis and improvement feasibility of high-rise building basement

• Main Authors: Yi-Loon Chiang, 江毅倫
• Other Authors: 朱錦洲
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/2zf2g7

碩士 === 國立臺灣大學 === 應用力學研究所 === 107 === Although there are many scholars studying the urban environmental wind field, it is rarely mentioned that the influence of high-rise buildings on the basement . Due to the high flow velocity on the windward side, strong winds flow into the basement opening in the windward side, causing the internal wind speed and pressure to rise, causing difficulties for personnel to walk and carry goods. The sound of strong wind passing through the slit is also heart-wrenching. In severe cases, the elevator equipment may be damaged and cannot be opened normally. This study uses Large Eddy Simulation to calculate high Reynolds number flows for high-rise buildings with a basement. In order to accurately simulate the flow field flow, a boundary layer grid is set in the near ground and the building. The inflow uses the exponential atmospheric boundary layer, and there is no slip condition around the building and the ground, and an exit is set in the outer flow field and the basement. The results show that the airflow into the basement is not close to the ground airflow, but the airflow at 1/2 to 2/3 of the height of the building, flowing through the ground and entering the basement through the upstream downwash vortex.Because the higher the boundary layer height is, the faster the velocity is. The airflow velocity into the basement is higher than the surface wind speed. The inflow of high-speed airflow will increase the inlet wind speed of the basement and the pressure at the elevator door. Analysis of the changes in different wind directions can be found that if the angle between the wind direction and the windward surface is larger, the secondary separation flow area at the entrance increases, reducing the airflow entering the basement and achieving the effect of reducing the pressure of the elevator door. If the appearance of the entrance to the basement is changed to block the inflow of air. If the appearance of the basement entrance is changed to block the inflow of airflow, it is found that adding a roof to the basement lane can effectively reduce the wind speed at the entrance and the elevator door pressure by more than 50%. The reduction in lane entry height is more effective in reducing elevator door pressure.