On the value of the von K & aacute;rm & aacute;n constant in the atmospheric surface layers over urban surfaces

Cheng, Wai-Chi1,2,3

2023-10-01

10.1016/j.jweia.2023.105547

JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS   Impact Factor & Quartile

0167-6105

1872-8197

Large-eddy simulations of turbulent boundary flow over different urban-like surfaces in neutrally stratified conditions are performed to study the atmospheric surface layer characteristics over urban areas. A simple method based on the vertical profile of the dimensionless velocity gradient is used to identify the inertial sublayer (ISL) in all cases. The results show that the mean wind profiles in the different urban ISLs can all be generally described by the logarithmic wind profile. However, for the idealized urban surfaces composed of regular building block arrays and the realistic urban surface case, the von Karman constant (x) in the ISL is found to be significantly smaller (in the range of 0.21-0.27) than the typically adopted value of 0.4. As x is a key constant in the parametrizations of urban surface flows and is usually assumed to be & AP; 0.4 in existing surface parametrization models, a significantly smaller x implies that large uncertainties may exist in the predictions of the momentum, heat, and scalar turbulent fluxes over urban surfaces using these models.

Atmospheric surface layer Large-eddy simulation Logarithmic wind profile von Karman constant Urban surfaces Mean wind profile

SCI

English

Corresponding

National Natural Science Foundation of China and Macau Science and Technology Development Joint Fund (NSFC-FDCT), China and Macau[41861164027]

Engineering ; Mechanics

Engineering, Civil ; Mechanics

WOS:001072012000001

ELSEVIER

ENGINEERING

Web of Science

1.Sun Yat sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China
2.Sun Yat sen Univ, Guangdong Prov Key Lab Climate Change & Nat Disast, Zhuhai, Peoples R China
3.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Shenzhen, Peoples R China

Cheng, Wai-Chi. On the value of the von K & aacute;rm & aacute;n constant in the atmospheric surface layers over urban surfaces[J]. JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS,2023,241.

Cheng, Wai-Chi.(2023).On the value of the von K & aacute;rm & aacute;n constant in the atmospheric surface layers over urban surfaces.JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS,241.

Cheng, Wai-Chi."On the value of the von K & aacute;rm & aacute;n constant in the atmospheric surface layers over urban surfaces".JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS 241(2023).