Statistical fluctuations due to microscale mixing in a diffusion layer
✍ Scribed by William B. Zimmerman; P. C. Chatwin
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 515 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1180-4009
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✦ Synopsis
Abstract
A new viewpoint on the evolution of scalar dispersion in a turbulent flow is taken by considering diffusion of a passive scalar where the measuring device is stochastically positioned. This is a model of a dispersion process where mixing at small scales occurs by molecular diffusion and large scale motions are rigid in regards to the internal cloud structure. Numerical results for the first four central moments are presented, and are shown to be consistent with theoretical approximations for both small and large times. The plot of kurtosis against skewness collapses onto a quadratic curve close to those discussed by Mole and Clarke, and others. The present work suggests that this robust feature has a rather simple basis in physics, and further research is proposed that will critically test this interpretation.