風洞實驗探討紊流邊界層通過不同斜坡地形之風場特性

• Main Author: 謝淳泰
• Other Authors: 蕭葆羲
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/71556285689817037284

碩士 === 國立海洋大學 === 河海工程學系 === 88 === Abstract To investigate the flow structure, series of Atmospheric boundary layer flow simulation with wind carried out different sloping terrains in the wind-tunnel. Results are summarized as the followings: (1)By suitable settlement of spires and roughness elements in the atmospheric environment wind-tunnel, it can be simulated that open-ground of neutral atmospheric boundary layer. (2)The maximum of the speed-up ratioΔS was found at windward slope top of the terrain and it will lower with the decrease of the sloping angle in sloping terrains. (3)The maximum of turbulence intensity was found at the front of the slopes and back of the top of the terrains. The value of turbulence intensity will lower with the decrease of the sloping angle. (4)With the increase of the slope, the distribution of Reynolds stresses will become diffuse. In each terrain the stress fraction S4 (sweep event) and S2 (ejection event) are similar at location close to ground. The hole size demonstrated that ejection and sweep are dominating the contribution of the Reynolds stress. And the difference of S4 and S2 will become unobvious with the change of sloping angle. (5)The non-dimensional turbulence spectrum indicates that energy containing eddies move to low frequency with the increase of height (Z/H). (6)The reaction of pressure will lower with the decrease of the sloping angle on the slope. Because pressure lowered suddenly, Cp will become negative at the front of the top. (7)Friction coefficient will grow up with the increase of the sloping angle on the slope. And it will lower with the increase of the sloping angle on the top of the terrains.