Large-Eddy Simulation and Parameterization of Decaying Turbulence in the Evening Transition of the Atmospheric Boundary Layer

Ткаченко, Е.В.; Дебольский, А.В.; Мортиков, Е.В.; Глазунов, А.В.

Авторы: Ткаченко Е.В., Дебольский А.В., Мортиков Е.В., Глазунов А.В.
Журнал: Izvestiya - Atmospheric and Oceanic Physics
Том: 58
Номер: 3
Год издания: 2022
Издательство: Pleiades Publishing, Ltd
Местоположение издательства: Road Town, United Kingdom
Первая страница: 219
Последняя страница: 236
DOI: 10.1134/S0001433822030112
Аннотация: This study presents the results of large-eddy simulation (LES) of the evening transition in theatmospheric boundary layer in the case of free convection and in the presence of geostrophic wind. The turbulent kinetic energy (TKE) balance and the dispersion dynamics of the velocity components are analyzed.It is shown that fast and slow decay periods can be distinguished within the transition. The differences in TKEanisotropy between these two periods are demonstrated. During the fast decay period, the majority of theenergy within the vertical component is consumed due to thermals inertial movement after the cease of convection. This is followed by the TKE redistribution into large-scale horizontal components, which leads tothe formation of quasi-horizontal turbulence, where the TKE dissipation is significantly slower in comparison to the isotropic state. It is shown that one-dimensional boundary-layer model, in which turbulent fluxesare parameterized by means of a two-equation closure, does not reproduce evening transition dynamics. Inparticular, the use of the gradient approximation in the one-dimensional model leads to the preservation ofthe convective distribution of the heat flux along the vertical during the transition period and additional TKEgeneration in the boundary layer due to the action of buoyancy forces. The use of the phenomenologicalequation for the dissipation rate leads to decreased TKE decay rate during the fast decay period and increasedTKE decay rate during the slow decay period. Possible approaches toward modification of the Reynolds-averaged Navier–Stokes (RANS) closures in order to correctly reproduce transition periods of the atmospheric boundary layer are discussed.
Добавил в систему: Ткаченко Екатерина Викторовна

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Large-Eddy Simulation and Parameterization of Decaying Turbulence in the Evening Transition of the Atmospheric Boundary Layerстатья

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