Correlations in a weakly interacting two-dimensional random flow

Autor: Kolokolov, I. V., Lebedev, V. V., Parfenyev, V. M.
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevE.109.035103
Popis: We analytically examine fluctuations of vorticity excited by an external random force in two-dimensional fluid. We develop the perturbation theory enabling one to calculate nonlinear corrections to correlation functions of the flow fluctuations found in the linear approximation. We calculate the correction to the pair correlation function and the triple correlation function. It enables us to establish the criterion of validity of the perturbation theory for different ratios of viscosity and bottom friction. We find that the corrections to the second moment are anomalously weak in the cases of small bottom friction and small viscosity and relate the weakness to the energy and enstrophy balances. We demonstrate that at small bottom friction the triple correlation function is characterized by universal scaling behavior in some region of lengths. The developed perturbation method was verified and confirmed by direct numerical simulations.
Databáze: arXiv