Mean and variance of the velocity of solid particles in turbulence
Even the simplest velocity statistics, i. e., the mean and the variance for particles moving in turbulence still offer challenges. This paper offers simple conceptual models/explanations for a couple of the most intriguing observations, namely, the enhanced settling rate in strong turbulence and the reduced Lagrangian velocity variance for even the smallest of sinking particles. While simultaneous experimental observation of the two effects still do not exist, we draw parallels between two classical sets of experiments, each exhibiting one, to argue that they are two sides of the same phenomenon: Selective sampling due to particle concentration on fast tracks like those illustrated by Maxey & Corrsin (1986).
KeywordsVortex Diesel Autocorrelation Advection Settling
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