Model of Turbulence with Many Time Scales in the Surface Layer of the Sea

Chukharev, A. M.

doi:10.7868/s0002351513040020

Cited by 2 publications

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“…Собранные в различных гидрометеорологических условиях экспериментальные данные о турбулентном режиме в верхнем перемешанном слое (с нейтральной стратификацией) позволили провести верификацию наиболее известных моделей турбулентного обмена для данного слоя. В число анализируемых моделей вошли модель пристеночного (логарифмического) слоя, возможность применения которой предложена в работе [22], модели, описанные в [23][24][25], а также многомасштабная модель [26], разработанная в отделе турбулентности МГИ.…”

Section: турбулентное перемешивание в верхнем квазиоднородном слоеunclassified

“…5. Результаты расчетов по многомасштабной модели Чухарева [26], как правило, соответствовали экспериментальным данным, но в ряде случаев наблюдалось заметное расхождение. Введение в модель вместо параметризаций непосредственно измеренных значений характеристик волнения и профиля скорости течения (особенно в верхнем трехметровом слое) явным образом улучшает соответствие результатов расчетов и экспериментов.…”

Section: турбулентное перемешивание в верхнем квазиоднородном слоеunclassified

“…Таким образом, из рассмотренных моделей наиболее предпочтительной для оценки интенсивности турбулентного обмена в приповерхностном слое моря оказалась модель Чухарева [26], расчеты по которой дают в большинстве случаев вполне удовлетворительное совпадение с экспериментальными данными, но использующиеся в ней (взятые из литературы) модельные зависимости характеристик волнения от скорости ветра и профиля скорости течения не всегда соответствуют фактическим значениям, что отражается на результатах.…”

Section: турбулентное перемешивание в верхнем квазиоднородном слоеunclassified

“…calculation by the Chukharev model [26]; coefficient approximation by a power function for the upper layer;…”

Section: турбулентное перемешивание в верхнем квазиоднородном слоеmentioning

confidence: 99%

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Basic Regularities of Vertical Turbulent Exchange in the Mixed and Stratified Layers of the Black Sea

Samodurov¹,

Chukharev²,

Kazakov³

2021

MGZh

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Purpose. The purpose of the study is to assess the coefficient of vertical turbulent exchange for different layers of the Black Sea basin based on the experimental data on microstructure of the physical fields obtained for the period 2004–2019 in the Black Sea and using the semi-empirical models. Methods and Results. For the upper mixed layer, the turbulent energy dissipation rate ɛ and the exchange coefficient were calculated using the velocity fluctuation spectra based on the Kolmogorov hypotheses on the turbulence spectrum inertial range. In the stratified layers, the turbulence coefficient and the dissipation rate were experimentally determined both from the spectra of the velocity horizontal fluctuations’ gradients and the vertical spectra of temperature fluctuations using the concept of the effective scale of turbulent spots. Depending on the features of the hydrological regime and the prevailing energy contributors to turbulence generation, five layers were identified and described (including their characteristic power dependences of the vertical turbulent diffusion coefficients K on the buoyancy frequency N) using the 1.5D-model of vertical turbulent exchange for the basin under study. For the stratified layers, the 1.5D-model results were comparatively analyzed with those of the other semi-empirical and theoretical models describing the most probable hydrophysical processes in each specific layer; the relations for the vertical turbulent exchange coefficient were obtained depending on the buoyancy frequency. Conclusions. Comparison of the experimental data collected under different hydrometeorological conditions with the simulations resulted from the known turbulence models for the sea upper layer showed that the best agreement between the simulation and measurement data was provided by a multiscale model taking into account three basic mechanisms of turbulence generation: current velocity shear, instability of wave motions, and wave breaking. The turbulent exchange coefficient dependencies on depth are conditioned by the affect of the turbulence dominant source at a given level. In the stratified layers, the exchange coefficient dependence on buoyancy frequency is determined by the hydrophysical processes in each layer; the relations obtained for individual layers indicate intensity of the contributions of vertical advection, internal wave breakings, turbulence diffusion and geothermal flux.

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Section: турбулентное перемешивание в верхнем квазиоднородном слоеunclassified

“…calculation by the Chukharev model [26]; coefficient approximation by a power function for the upper layer;…”

Section: турбулентное перемешивание в верхнем квазиоднородном слоеmentioning

confidence: 99%

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Basic Regularities of Vertical Turbulent Exchange in the Mixed and Stratified Layers of the Black Sea

Samodurov¹,

Chukharev²,

Kazakov³

2021

MGZh

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Turbulent Exchange in Unsteady Air-Sea Interaction at Small and Submesoscales

Chukharev,

Pavlov

2024

Izvestiâ Akademii nauk SSSR. Fizika atmosfery i okeana

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An adequate description of the interaction between the atmosphere and ocean remains one of the most important problems of modern oceanology and climatology. An extremely wide variety of physical processes occurring in the coupled layers, a large range of scales, a moving boundary, all this factors significantly complicates the creation of models that would allow calculating the physical characteristics in both media with the necessary accuracy. In this paper the temporal variability of dynamic parameters in the driving layer of the atmosphere and in the near-surface layer of the sea on small and sub-mesoscales from one to several tens of hours is considered. The collected experimental data show a very high correlation between the dynamic wind speed and turbulence intensity in the upper sea layer on all scales recorded. An important distinguishing feature of all measured physical quantities in both media is the presence of quasi-periodic oscillations with different periods. For a more accurate description of momentum and energy fluxes from the atmosphere a non-stationary model of turbulent exchange in the near-surface layer of the sea is proposed. The model takes into account quasi-periodicity in the intensity of dynamic interaction between the atmosphere and the sea at these scales. In the model we use the equations of momentum and turbulent energy balance, the system of equations is solved numerically, the calculation results are compared with other models and with experimental data. It is shown that taking into account the non-stationarity of the wind strain improves the correspondence between the calculations and the experimental data. It is noted that in the nonstationary case, the energy and momentum flux from the atmosphere and the turbulence intensity increases compared to the action of a constant average wind of the same duration. Therefore, the strong averaging often used in global models may markedly underestimate the intensity of the dynamic interaction between the atmosphere and ocean.

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Model of Turbulence with Many Time Scales in the Surface Layer of the Sea

Cited by 2 publications

References 0 publications

Basic Regularities of Vertical Turbulent Exchange in the Mixed and Stratified Layers of the Black Sea

Basic Regularities of Vertical Turbulent Exchange in the Mixed and Stratified Layers of the Black Sea

Turbulent Exchange in Unsteady Air-Sea Interaction at Small and Submesoscales

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