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Diffussion of a scalar field in a compressible turbulent medium
Author(s) -
Silant'Ev N. A.,
Korolkov M. D.
Publication year - 1990
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.2113110208
Subject(s) - physics , turbulence , scalar (mathematics) , compressibility , scalar field , isotropy , turbulent diffusion , homogeneous , thermal diffusivity , vector field , homogeneous isotropic turbulence , field (mathematics) , classical mechanics , mathematical physics , mechanics , direct numerical simulation , thermodynamics , geometry , optics , mathematics , reynolds number , pure mathematics
The diffusion of scalar fields (temperature, density number of some admixture) in a compressible medium showing an isotropic, homogeneous and stationary turbulence is considered. The derived formulae for turbulent diffusivity χ T (ξ) hold up to ξ ≈ 1, where ξ = u 0 τ 0 / R 0 ( u 0 , τ 0 , and R 0 are characteristic velocity, life‐time, and correlation length of turbulent pulsations, respectively. The velocity field of turbulent motions u ( r, t ) is assumed to be known and the influence of the scalar field onto u ( r, t ) is neglected. It is shown that the velocity correlators, which change their signs in dependence on the space corrdinates, may give negative values for ξ T (ξ) when ξ ≠ 0.