Calibrating passive scalar transport in shear-flow turbulence
2010 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 82, no 1, 16304Article in journal (Refereed) Published
The turbulent diffusivity tensor is determined for linear shear-flow turbulence using numerical simulations. For moderately strong shear, the diagonal components are found to increase quadratically with Peclet and Reynolds numbers below about 10 and then become constant. The diffusivity tensor is found to have components proportional to the symmetric and antisymmetric parts of the velocity gradient matrix, as well as products of these. All components decrease with the wave number of the mean field in a Lorentzian fashion. The components of the diffusivity tensor are found not to depend significantly on the presence of helicity in the turbulence. The signs of the leading terms in the expression for the diffusion tensor are found to be in good agreement with estimates based on a simple closure assumption.
Place, publisher, year, edition, pages
2010. Vol. 82, no 1, 16304
IdentifiersURN: urn:nbn:se:su:diva-49205DOI: 10.1103/PhysRevE.82.016304ISI: 000279693300001OAI: oai:DiVA.org:su-49205DiVA: diva2:377026
authorCount :22010-12-132010-12-132015-07-29Bibliographically approved