Modulation of fine-scale velocity gradient phenomena by concurrent large-scale velocity fluctuations in a developed shear flow

Conference paper (2015)

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Published Date

25-08-2015

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Abstract

The interaction between the large-scale velocity fluctuations (uL) and the small-scale velocity gradient phenomena, such as dissipation and the vortex stretching term, are examined in a turbulent free-shear flow. The difference between the probability density functions of these small-scale quantities conditioned on the sign of uL is quantified by means of the Kullback-Leibler divergence. It is observed that the interaction between uL and the velocity gradient phenomena is maximised at a filter length of 4λ, where λ is the Taylor length-scale. It is postulated that this is consistent with a mean shear mechanism.