A laboratory study of internal gravity waves incident upon slopes with varying surface roughness

He, Yu-Hao1,2,3; Cheng, Bu-Ying-Chao3; Xia, Ke-Qing1,2,3,4

2022-05-20

10.1017/jfm.2022.371

JOURNAL OF FLUID MECHANICS   影响因子和分区

0022-1120

1469-7645

We report a laboratory study on the scattering, energy dissipation and mean flow induced by internal gravity waves incident upon slopes with varying surface roughness. The experiment was performed in a rectangular box filled with thermally stratified water. The roughness of the slope surface, lambda, defined as the height of a roughness element over its base width, and the off-criticality gamma = (alpha - beta)/alpha and beta being the angles of the incident wave and the slope, are used as two control parameters. The distribution of energy dissipation in the direction normal to the slope is found to be more uniform in the rough surface cases. Counter-intuitively, both the maximum value in the dissipation profile and the total energy dissipation near the slope are reduced by surface roughness under most circumstances. The measured peak width (the full width at half-maximum of the peaks) of the dissipation profile is found to be broadened significantly in the rough surface cases. We also observed that there exists a non-zero optimal off-criticality (gamma = 0.17 for the present measurement resolution) for the normalized average dissipation and total dissipation, which may be due to the strongest wave energy near the slope at this gamma. Unlike surface roughness, the off-criticality has a small effect on the distribution of energy dissipation. Moreover, surface roughness is also found to change the structure of the scattering-induced mean flow and enhance its strength. The present study provides new perspectives on how the surface roughness on topographic features influences energy dissipation.

internal waves topographic effects

SCI ; EI

英语

第一 ; 通讯

National Natural Science Foundation of China[12072144] ; Research Grants Council (RGC) of HKSAR["CUHK14301115","CUHK14302317"] ; Department of Science and Technology of Guangdong Province[2019B21203001]

Mechanics ; Physics

Mechanics ; Physics, Fluids & Plasmas

WOS:000797958700001

CAMBRIDGE UNIV PRESS

20222312186982

Criticality (nuclear fission) ; Energy dissipation ; Gravity waves ; Surface measurement ; Surface scattering ; Wave energy conversion

Energy Losses (industrial and residential):525.4 ; Wave Energy:615.6 ; Nuclear Reactors:621 ; Classical Physics; Quantum Theory; Relativity:931 ; Physical Properties of Gases, Liquids and Solids:931.2 ; Gravitation, Relativity and String Theory:931.5 ; Fission and Fusion Reactions:932.2.1 ; Mechanical Variables Measurements:943.2

ENGINEERING

Web of Science

1.Southern Univ Sci & Technol, Ctr Complex Flows & Soft Matter Res, Shenzhen 518055, Peoples R China
2.Southern Univ Sci & Technol, Dept Mech & Aerosp Engn, Shenzhen 518055, Peoples R China
3.Chinese Univ Hong Kong, Dept Phys, Hong Kong, Peoples R China
4.Southern Univ Sci & Technol, Guangdong Prov Key Lab Turbulence Res & Applicat, Shenzhen 518055, Peoples R China

He, Yu-Hao,Cheng, Bu-Ying-Chao,Xia, Ke-Qing. A laboratory study of internal gravity waves incident upon slopes with varying surface roughness[J]. JOURNAL OF FLUID MECHANICS,2022,942.

He, Yu-Hao,Cheng, Bu-Ying-Chao,&Xia, Ke-Qing.(2022).A laboratory study of internal gravity waves incident upon slopes with varying surface roughness.JOURNAL OF FLUID MECHANICS,942.

He, Yu-Hao,et al."A laboratory study of internal gravity waves incident upon slopes with varying surface roughness".JOURNAL OF FLUID MECHANICS 942(2022).