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Wind and Structures Volume 40, Number 3, March 2025 , pages 193-205 DOI: https://doi.org/10.12989/was.2025.40.3.193 |
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Experimental study on the effect of surface roughness on the characteristics of a plane wall jet |
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Yongli Zhong, Yichen Liu, Bowei Liu, Xiangjun Tan, Zhitao Yan and Xiaogang Yang
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| Abstract | ||
| Surface roughness reflects the obstructive effect of surface features on atmospheric turbulence, and is a key factor influencing the characterization of the near-surface wind field. In this study, the method for measuring roughness in the atmospheric boundary layer was introduced to investigate the effect of surface roughness on the wind profile shape and turbulence characteristics of downbursts. Different roughness landforms in nature were simulated by arranging roughness elements with various sizes and distribution densities. Subsequently, wind field experiments of the downburst outflow section were carried out. The results show that roughness has a strong decay effect on streamwise wind speed; as the surface roughness increases, the vertical height corresponding to the maximum wind speed increases. Meanwhile, the turbulence intensity in the inner layer of the wall jet increases significantly, but the turbulence intensity in the outer layer decreases gradually. To address the problem that the existing empirical models of vertical wind profiles for horizontal wind speeds of downburst are unsuitable for all rough landforms, equations for fitting vertical wind profiles for different rough landforms are proposed. In addition, the surface roughness significantly affects the Reynolds stress in the inner layer of the wall jet. The analysis reveals that the wall jet still follows a dimensionless law in high Reynolds number tests with different surface roughness. The study further provides some references for downburst wind loads considering roughness. | ||
| Key Words | ||
| surface roughness; wall jet; wind field characteristic; wind profile; wind tunnel test | ||
| Address | ||
| Yongli Zhong:School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China Yichen Liu:School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China Bowei Liu:School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China Xiangjun Tan:School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China Zhitao Yan:1)School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China 2)School of Civil Engineering, Chongqing University, Chongqing 400045, China Xiaogang Yang:School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, Chongqing 401331, China | ||