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Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

1994

Selected Works

Iowa State University

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Full-Text Articles in Mechanical Engineering

Improved Fokker–Planck Model For The Joint Scalar, Scalar Gradient Pdf, Rodney O. Fox Jan 1994

Improved Fokker–Planck Model For The Joint Scalar, Scalar Gradient Pdf, Rodney O. Fox

Rodney O. Fox

The joint scalar, scalar gradient probability density function (PDF) of an inert nonpremixed scalar diffusing in a one-dimensional system of random-sized lamellas is investigated by numerical simulation. The form of the scalar PDF, at a given RMS value, is nearly identical to that predicted by direct numerical simulation (DNS) of scalar mixing in isotropic turbulence and the mapping closure, and the moments of both the scalar and the scalar gradient suggest that their limiting marginal PDF are Gaussian. The joint scalar, scalar gradient PDF is found to be restricted to a bounded region in the scalar-scalar gradient plane, whose form …