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JOURNAL OF DESERT RESEARCH  2012, Vol. 32 Issue (6): 1534-1541    DOI:
Desert and Desertification     
The Integrated Effects of Roughness Elements Geometric Parameters on Aerodynamic Roughness Length
MEI Fan-min1,2, JIANG Chan-wen1, JIANG Shan-shan1, WANG Tao2
1.School of Environmental and Chemical engineering, Xian Polytechnic University, Xi'an 710048, China;
2.Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
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Abstract  

Aerodynamic roughness lengths over surfaces were investigated by a wind tunnel experiment so as to understand integrated effects of roughness elements’ height, density, spacing, porous index and aspect ratios on aerodynamic roughness length. Results indicate that normalized aerodynamic roughness lengths (ratio of aerodynamic roughness length to roughness element height) over compact and porous roughness elements are direct proportional to roughness elements densities, and the proportionality coefficient is a quantitative reflection of the integrated effects of roughness elements’ geometric parameters on roughness lengths. A multiple variant model of aerodynamic roughness is proposed on basis of the integrated effect of geometric parameters (roughness element height h, roughness element density λ, ratio of spacing between two adjacent individual roughness elements to height Sp, and aspect ratio of individual roughness elements AR) on aerodynamic roughness length: Z0h=-0.0028+0.5403S0.32p·AR-0.07·λ.  This new model improves significantly simulation accuracy and expands application scope of some previous models.

Key words:  roughness element      aerodynamic roughness length      geometric parameter      model     
Received:  26 April 2012      Published:  08 June 2012
ZTFLH:  X169  

Cite this article: 

MEI Fan-min1,2, JIANG Chan-wen1, JIANG Shan-shan1, WANG Tao2. The Integrated Effects of Roughness Elements Geometric Parameters on Aerodynamic Roughness Length. JOURNAL OF DESERT RESEARCH, 2012, 32(6): 1534-1541.

URL: 

http://www.desert.ac.cn/EN/     OR     http://www.desert.ac.cn/EN/Y2012/V32/I6/1534

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