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Article Dans Une Revue Physical Review Fluids Année : 2021

Eulerian spatiotemporal correlations in passive scalar turbulence

Résumé

We study the spatiotemporal two-point correlation function of passively advected scalar fields in the inertial-convective range in three-dimensional homogeneous isotropic turbulence by means of numerical simulations. Our aim is to make a precision test of analytical results recently obtained using functional renormalization group (FRG). We show that at small time delays t, the Eulerian correlations of the scalar decay as a Gaussian in the variable tp where p is the wave number, as established by FRG, and which is related to the sweeping effect. At large time delays, a crossover to an exponential decay in tp2 is predicted by the FRG analysis, but not observable in simulations due to numerical noise. We then propose to study this regime for a scalar field advected by a Kraichnan synthetic velocity field, and accurately confirm the FRG result, including the precise form of the prefactor in the exponential. By introducing finite time correlations in the synthetic velocity field, we also uncover the crossover between the two regimes.
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Dates et versions

hal-03266110 , version 1 (18-07-2022)

Identifiants

Citer

Anastasiia Gorbunova, Carlo Pagani, Guillaume Balarac, Léonie Canet, Vincent Rossetto. Eulerian spatiotemporal correlations in passive scalar turbulence. Physical Review Fluids, 2021, 6 (12), pp.124606. ⟨10.1103/PhysRevFluids.6.124606⟩. ⟨hal-03266110⟩
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