Statistics of surface divergence and their relation to air‐water gas transfer velocity

Asher, William E.; Liang, Hanzhuang; Zappa, Christopher J.; Loewen, Mark; Mukto, Moniz; Litchendorf, Trina; Jessup, Andrew T.

doi:10.1029/2011jc007390

Cited by 9 publications

(9 citation statements)

References 38 publications

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“…For comparison, a group of laboratory studies were selected from the literature with simultaneous measurements of surface divergence and gas transfer velocity. The selected studies involved different turbulence generation mechanisms, including grid‐stirred turbulence [ McKenna and McGillis , ; Herlina and Jirka , ], wind sheared turbulence [ Turney et al ., ; Turney and Banerjee , ], wind shear combined with random jet stirring [ Asher et al ., ], and open channel flows [ Turney and Banerjee , ]. All gas transfer velocities were converted to k 600 and plotted against

\sqrt{D β'}

in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Turbulence in Asher et al . [] was a result of a combination of random jets and surface wind shear. It is not clear how the Reynolds number can be determined based on bulk flow parameters as multiple velocity and length scales could coexist.…”

Section: Resultsmentioning

confidence: 99%

“…In a laboratory investigation, Asher et al . [] proved that

β'

scales with the surface renewal time of measured pH value and of the surface temperature as well. The surface divergence can also be evaluated by measuring the vertical gradient of vertical fluctuating component:

β' = \sqrt{\overset{true¯}{{true(\frac{\partial w'}{\partial z} true)}^{2}}} |_{i n t},

where

\frac{\partial w'}{\partial z}

can be measured along the surface normal direction at the aqueous side with a PIV system [ Herlina and Jirka , ; Asher et al ., ].…”

Section: Introductionmentioning

confidence: 99%

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On the coefficients of small eddy and surface divergence models for the air‐water gas transfer velocity

et al. 2015

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Recent studies suggested that under low to moderate wind conditions without bubble entraining wave breaking, the air-water gas transfer velocity k 1 can be mechanistically parameterized by the nearsurface turbulence, following the small eddy model (SEM). Field measurements have supported this model in a variety of environmental forcing systems. Alternatively, surface divergence model (SDM) has also been shown to predict the gas transfer velocity across the air-water interface in laboratory settings. However, the empirically determined model coefficients (a in SEM and c 1 in SDM) scattered over a wide range. Here we present the first field measurement of the near-surface turbulence with a novel floating PIV system on Lake Michigan, which allows us to evaluate the SEM and SDM in situ in the natural environment. k 1 was derived from the CO 2 flux that was measured simultaneously with a floating gas chamber. Measured results indicate that a and c 1 are not universal constants. Regression analysis showed that a $ logðeÞ while the near-surface turbulence dissipation rate e is approximately greater than 10 26 m 2 s 23 according to data measured for this study as well as from other published results measured in similar environments or in laboratory settings. It also showed that a scales linearly with the turbulent Reynolds number. Similarly, coefficient c 1 in the SDM was found to linearly scale with the Reynolds number. These findings suggest that larger eddies are also important parameters, and the dissipation rate in the SEM or the surface divergence b 0 in the SDM alone may not be adequate to determine k 1 completely.

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\sqrt{D β'}

in Figure .…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…In a laboratory investigation, Asher et al . [] proved that

β'

β' = \sqrt{\overset{true¯}{{true(\frac{\partial w'}{\partial z} true)}^{2}}} |_{i n t},

where

\frac{\partial w'}{\partial z}

can be measured along the surface normal direction at the aqueous side with a PIV system [ Herlina and Jirka , ; Asher et al ., ].…”

Section: Introductionmentioning

confidence: 99%

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On the coefficients of small eddy and surface divergence models for the air‐water gas transfer velocity

et al. 2015

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“…[], Nagaosa [], and Asher et al . []. More support for the close relationship between gas flux and surface divergence was provided by Hasegawa and Kasagi [], Takagaki et al .…”

Section: Introductionmentioning

confidence: 86%

Boundary layers at a dynamic interface: Air‐sea exchange of heat and mass

Szeri

2017

JGR Oceans

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Exchange of mass or heat across a turbulent liquid‐gas interface is a problem of critical interest, especially in air‐sea transfer of natural and anthropogenic gases involved in the study of climate. The goal in this research area is to determine the gas flux from air to sea or vice versa. For sparingly soluble nonreactive gases, this is controlled by liquid phase turbulent velocity fluctuations that act on the thin species concentration boundary layer on the liquid side of the interface. If the fluctuations in surface‐normal velocity w′ and gas concentration c′ are known, then it is possible to determine the turbulent contribution to the gas flux. However, there is no suitable fundamental direct approach in the general case where neither w′ nor c′ can be easily measured. A new approach is presented to deduce key aspects about the near‐surface turbulent motions from measurements that can be taken by an infrared (IR) camera. An equation is derived with inputs being the surface temperature and heat flux, and a solution method developed for the surface‐normal strain experienced over time by boundary layers at the interface. Because the thermal and concentration boundary layers experience the same near‐surface fluid motions, the solution for the surface‐normal strain determines the gas flux or gas transfer velocity. Examples illustrate the approach in the cases of complete surface renewal, partial surface renewal, and insolation. The prospects for use of the approach in flows characterized by sheared interfaces or rapid boundary layer straining are explored.

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“…Examples are the gas transfer across airwater interfaces in geophysical flows as lakes, rivers, estuaries and oceans; or the transfer of chemical species between phases in unit operations of industrial procedures, like the manufacture of petrochemicals, the production of pharmaceuticals, and the sewage treatment. Different aspects of interfacial transfer may be found in Asher et al [1], Demars and Manson [2], Nguyen and Tan [3], Krah [4], among others.…”

Section: Introductionmentioning

confidence: 99%

Solutions of scalar mean profiles close to gas–liquid interfaces under turbulent free slip motion

Schulz¹,

Gonçalves²

2015

Computational Methods in Multiphase Flow VIII

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Mean profiles of scalar properties close to moving gas-liquid interfaces subjected to turbulence are quantified using Random Square Waves (RSW). The condition of stationary turbulent transfer allows reducing the third order nonlinear governing equation successively to a second order and to a first order equation, which admits theoretical integration, furnishing the set of solutions analyzed in the present study. It is shown that different solutions may apply to different parts of the calculation domain (physical domain). It is also shown that the stationary problem admits a linear profile close to the gas-liquid interface, while a nonlinear function describes the mean properties apart from the interface.

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Statistics of surface divergence and their relation to air‐water gas transfer velocity

Cited by 9 publications

References 38 publications

On the coefficients of small eddy and surface divergence models for the air‐water gas transfer velocity

On the coefficients of small eddy and surface divergence models for the air‐water gas transfer velocity

Boundary layers at a dynamic interface: Air‐sea exchange of heat and mass

Solutions of scalar mean profiles close to gas–liquid interfaces under turbulent free slip motion

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