Laboratory investigation of air-sea momentum transfer under severe wind conditions

2020 ◽  
Author(s):  
Maksim Vdovin ◽  
Georgy Baydakov ◽  
Daniil Sergeev ◽  
Yuliya Troitskaya
Keyword(s):  
Wind Speed ◽  
Data Processing ◽  
Drag Coefficient ◽  
Financial Support ◽  
Water Surface ◽  
Wind Wave ◽  
Aerodynamic Resistance ◽  
Sea Surface ◽  
Surface Drag ◽  
Wave Flume

<p>Wind-wave interaction at extreme wind speed is of special interest now in connection with the problem of explanation of the sea surface drag saturation at the wind speed exceeding 30 m/s. Now it is established that at hurricane wind speed the sea surface drag coefficient is significantly reduced in comparison with the parameterization obtained at moderate to strong wind conditions.</p><p>The subject of this work is investigation of aerodynamic resistance of the waved water surface under severe wind conditions (up to U10 ≈ 50 m/s). Laboratory experiments were carried out at the new high-speed wind-wave flume in the Large Thermally Stratified Tank (at the Institute of Applied Physics, Russia) built in 2019. The main difference between the new wind-wave flume and the old one is the absence of a pressure gradient along the main axis of the new flume. Aerodynamic resistance of the water surface was measured by the profile method with Pitot tube. A method for data processing taking into account the self-similarity of the air flow velocity profile in the aerodynamic tube was applied for retrieving wind friction velocity and surface drag coefficients. Simultaneously with the airflow velocity measurements, the wind-wave field parameters in the flume were investigated by system of wire gauges.</p><p>Analysis of the wind velocity profiles and wind-wave spectra showed tendency to decrease for surface drag coefficient for wind speed exceeding 25 m/s simultaneously with the mean square slope and significant wave height.</p><p><span>Acknowledgments</span> <br>This work was carried out with the financial support of the RFBR according to the research project 18-55-50005, 20-05-00322, 18-35-20068, 18-05-00265. Data processing was carried out with the financial support of Russian Science Foundation grant 19-17-00209.</p>

Dependence of sea surface drag coefficient on wind-wave parameters

2011 ◽  
Vol 30 (2) ◽  
pp. 14-24 ◽  
Author(s):  
Jian Shi ◽  
Zhong Zhong ◽  
Ruijie Li ◽  
Yan Li ◽  
Wenyu Sha
Keyword(s):  
Drag Coefficient ◽  
Wind Wave ◽  
Sea Surface ◽  
Surface Drag ◽  
Wave Parameters

scholarly journals Parameterization of Sea Surface Drag Coefficient for All Wind Regimes Using 11 Aircraft Eddy-Covariance Measurement Databases

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1485
Author(s):  
Zhiqiu Gao ◽  
Shaohui Zhou ◽  
Jianbin Zhang ◽  
Zhihua Zeng ◽  
Xueyan Bi
Keyword(s):  
Wind Speed ◽  
Transfer Coefficient ◽  
Drag Coefficient ◽  
Sea Surface ◽  
Turbulent Heat Transfer ◽  
Horizontal Wind ◽  
Turbulent Heat ◽  
Mean Flow ◽  
Surface Drag ◽  
Horizontal Wind Speed

The drag coefficient is essential for calculating the aerodynamic friction between air and sea. In this study, we regress a set of relationships between the drag coefficient and the wind speed for different wind ranges using an observational dataset that consists of 5941 estimates of the mean flow and fluxes from 11 aircraft turbulent measurements over the sea surface. Results show that: (1) the drag coefficient is a power function of wind speed over smooth sea surface when it is no greater than 4.5 ms−1, and the drag coefficient decreases with the increase of wind speed; and (2) for rough sea surface, when the wind speed is greater than 4.5 ms−1 and less than or equal to 10.5 ms−1, the drag coefficient increases linearly with the increase of horizontal wind speed; when the wind speed is greater than 10.5 ms−1 and less than or equal to 33.5 ms−1, the drag coefficient changes parabolically with the increase of wind speed; when the wind speed is greater than 33.5 ms−1, the drag coefficient is constant. Additionally, regressed from drag coefficient, the saturated wind speed threshold is 23 ms−1. Parameterizations of turbulent heat transfer coefficient (Ch) and water vapor transfer coefficient (Ce) are also investigated.

scholarly journals Study on Wind Speed Dependency of Sea Surface Drag Coefficient Based on Observed Wave Data

2013 ◽  
Vol 69 (2) ◽  
pp. I_136-I_140
Author(s):  
Masaki YOKOTA ◽  
Noriaki HASHIMOTO ◽  
Ryota AMIYA ◽  
Mitsuyoshi KODAMA
Keyword(s):  
Wind Speed ◽  
Drag Coefficient ◽  
Sea Surface ◽  
Surface Drag ◽  
Wave Data

scholarly journals The Effect of Foam on Waves and the Aerodynamic Roughness of the Water Surface at High Winds

2019 ◽  
Vol 49 (4) ◽  
pp. 959-981 ◽  
Author(s):  
Yu. Troitskaya ◽  
D. Sergeev ◽  
A. Kandaurov ◽  
M. Vdovin ◽  
S. Zilitinkevich
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Drag Coefficient ◽  
Surface Waves ◽  
Water Surface ◽  
Eddy Viscosity ◽  
Surface Drag ◽  
Momentum Exchange ◽  
High Winds

AbstractThis paper models the impact of the presence of foam on the short-wave component of surface waves and momentum exchange in the atmospheric boundary layer at high winds. First, physical experiments were carried out in a wind-wave flume in which foam can be artificially produced at the water surface. Tests were conducted under high-wind-speed conditions where equivalent 10-m wind speed ranged from 12 to 38 m s−1, with measurements made of the airflow parameters, the frequency–wavenumber spectra of the surface waves, the foam coverage of the water surface, and the distribution of the foam bubbles. Analysis of the resulting data indicates that the surface drag coefficient correlates with the fraction of foam coverage and the mean square slope (MSS) of the water surface, and that, at a certain wind speed, the MSS decreases with an increase in the fraction of foam coverage. Based on these results, we suggest a simple model for eddy viscosity in the turbulent boundary layer over a fractionally foam-covered wave surface. The measurements in a laboratory environment are shown to be in good agreement with the predictions of a quasi-linear model of the atmospheric boundary layer over a waved water surface that adopts this eddy viscosity. Adaptation of the proposed model to field conditions is discussed, and the synergetic effect of foam at the water surface and spray in the marine atmospheric boundary layer on ocean surface resistance at high winds is estimated so as to be able to explain the observed peaking dependence of the surface drag coefficient on the 10-m wind speed.

scholarly journals A Novel Sea Surface Roughness Parameterization Based on Wave State and Sea Foam

2021 ◽  
Vol 9 (3) ◽  
pp. 246
Author(s):  
Difu Sun ◽  
Junqiang Song ◽  
Xiaoyong Li ◽  
Kaijun Ren ◽  
Hongze Leng
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Drag Coefficient ◽  
Sea Surface ◽  
High Wind Speed ◽  
Wave State ◽  
Wind Speeds ◽  
Sea Surface Roughness ◽  
Extreme Wind ◽  
The Impact

A wave state related sea surface roughness parameterization scheme that takes into account the impact of sea foam is proposed in this study. Using eight observational datasets, the performances of two most widely used wave state related parameterizations are examined under various wave conditions. Based on the different performances of two wave state related parameterizations under different wave state, and by introducing the effect of sea foam, a new sea surface roughness parameterization suitable for low to extreme wind conditions is proposed. The behaviors of drag coefficient predicted by the proposed parameterization match the field and laboratory measurements well. It is shown that the drag coefficient increases with the increasing wind speed under low and moderate wind speed conditions, and then decreases with increasing wind speed, due to the effect of sea foam under high wind speed conditions. The maximum values of the drag coefficient are reached when the 10 m wind speeds are in the range of 30–35 m/s.

scholarly journals Sea Surface Drag Fluctuation in Relation to the Saturation Ratio of Wind Wave Spectrum

2010 ◽  
Vol 66 (1) ◽  
pp. 101-105
Author(s):  
Yasushi SUZUKI ◽  
Yoshiaki TOBA ◽  
Naoya SUZUKI ◽  
Satoru KOMORI
Keyword(s):  
Wind Wave ◽  
Wave Spectrum ◽  
Sea Surface ◽  
Surface Drag ◽  
Saturation Ratio

scholarly journals Relationship between Sea Surface Drag Coefficient and Wave State

2021 ◽  
Vol 9 (11) ◽  
pp. 1248
Author(s):  
Jian Shi ◽  
Zhihao Feng ◽  
Yuan Sun ◽  
Xueyan Zhang ◽  
Wenjing Zhang ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Momentum Flux ◽  
Sea Surface ◽  
Sea Spray ◽  
Wave Age ◽  
High Wind ◽  
Surface Drag ◽  
Wave State ◽  
Wind Speeds ◽  
Strong Winds

The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (CD) does not increase linearly with the increasing wind speed, namely, the increase of CD is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective CD (CD, eff) under strong winds. Our results indicate that wave age plays an important role in determining CD. When the wave age is >0.4, CD decreases with the wave age. However, when the wave age is ≤0.4, CD increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds.

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