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Author(s):
S. Goto and S. Kida
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Title:
Passive Scalar Spectrum in Isotropic Turbulence: Prediction by the Lagrangian Direct-interaction Approximation
Date of publication:
June 1998
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Key words:
Turbulence, Passive Scalar, Direct-Interaction Approximation
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Abstract:
A closed set of equations for the passive scalar correlation function in isotropic turbulence is formulated by the Lagrangian direct-interaction approximation developed previously by the present authors [ Kida and Goto, J. Fluid Mech. 345, 307 (1997) ]. We examine the behavior of solutions to the resultant equations for arbitrary values of the Schmidt number, and show systematically that this closure theory is completely consistent with the phenomenological theories on the scalar spectrum function by Obukhov (1949), Corrsin (1951), Batchelor et al. (1959) and Batchelor (1959). The universal form of the function in the statistically stationary state is obtained by solving the closure equations numerically in the whole wavenumber range for each case of moderate, extremely large and small values of the Schmidt number.
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