Séminaire ISTerre

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Statistical properties of rapidly rotating turbulence

jeudi 16 décembre 2021 - 10h00

Manohar Sharma - ISTerre
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Turbulence is ubiquitous, and it is observed at every scale, i.e. from the cup of tea to galaxy formation. Turbulent flows are characterized by randomness in velocity fields, enhanced diffusivity, and strong nonlinearity in the flow. The three-dimensional turbulent flow is homogeneous and isotropic, but the rotation makes the flow anisotropic. The Coriolis force, owing to rotation, does not contribute to the total energy of the system. However, it modifies the energy distribution in different scales of the system such that the flow behaves like quasi-two-dimensional at a very high rotation rate. We study the statistical properties of the rotating turbulent flow numerically. We solve the governing equation of the system in a three-dimensional cubic periodic box. In this talk, I will start with the statistical behaviour of the decaying rotating turbulence and our proposed model. Here, we show that our proposed model is in good agreement with numerical results. We also show that the most dominant energetic modes in the system are (±1,0,0) and (0,±1,0) in the Fourier space. Most of the energy is trapped on large scales. Furthermore, we discuss the behaviour of the kinetic energy spectrum for the forced rotating turbulence. In this part of the talk, we discuss the behaviour of the kinetic energy spectrum in the two wavenumber regions— smaller than the forcing wavenumber and greater than the forcing wavenumber regions. We end the discussion by comparing the anisotropic energy transfers for the decaying and the forced rotating turbulent flows.

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Equipe organisatrice : Géodynamo

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères