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Friday, March 11, 2011
11:00 AM - 12:00 PM
CNLS Conference Room (TA-3, Bldg 1690)

Seminar

Passive scalar transport in peripheral regions of random flows

V. Lebedev
Director, Landau Institute for Theoretical Physics, Moscow

A. Chernykh and V. Lebedev (speaker) We investigate statistical properties of the passive scalar mixing in random (turbulent) flows assuming weakness of its diffusion. Then at advanced stages of the passive scalar decay its unmixed residue is concentrated primarily in a narrow diffusive layer near the wall and its transport to bulk goes through the peripheral region (laminar sublayer of the flow). We conducted Lagrangian numerical simulations of the process for different space dimensions $d$ and revealed structures responsible for the transport that are passive scalar tongues pulled from the diffusive boundary layer to bulk. We investigated statistical properties of the passive scalar and of the passive scalar integrated along the wall. Moments of both objects demonstrate scaling behavior outside the diffusive boundary layer. We propose an analytical scheme for the passive scalar statistics, explaining the features observed numerically.

Host: Misha Chertkov, chertkov@lanl.gov, 665-8119