Abstract
Three-dimensional turbulence simulations are used to show that the turbulent root mean square velocity is an upper bound of the speed of turbulent diffusion. There is a close analogy to magnetic diffusion where the maximum diffusion speed is the speed of light. Mathematically, this is caused by the inclusion of the Faraday displacement current which ensures that causality is obeyed. In turbulent diffusion, a term similar to the displacement current emerges quite naturally when the minimal tau approximation is used. Simulations confirm the presence of such a term and give a quantitative measure of its relative importance.
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© 2005 Springer-Verlag Berlin Heidelberg
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Brandenburg, A., Käpylä, P.J., Mohammed, A. (2005). Passive Scalar Diffusion as a Damped Wave. In: Peinke, J., Kittel, A., Barth, S., Oberlack, M. (eds) Progress in Turbulence. Springer Proceedings in Physics, vol 101. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-27401-4_1
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DOI: https://doi.org/10.1007/3-540-27401-4_1
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-23216-2
Online ISBN: 978-3-540-27401-8
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