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Mogens V. Melander

Publications and source records attributed to Mogens V. Melander.

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Intermittency via Self-Similarity -- An Analytic Example

Turbulence is known to show intermittency. That is, statistical properties vary with the length scale in a way not accounted for by statistical similarity where dimensionless ratios of moments are constant. Intermittency occurs even in the inertial range of isotropic turbulence, where physical intuition calls for a self-similar scale dependence. Perceived as a lack of overall scaling invariance, inertial range intermittency has become known as anomalous scaling. We present an analytic example demonstrating how anomalous scaling and self-similarity in the form of global scaling invariance can coexist within the same statistics. Whether we observe anomalous scaling or self-similarity depends on which variables we consider. Our example illustrates consequences of a symmetry, but is not meant as an intermittency model.

physics.flu-dyn

A Theory of Inertial Range Similarity in Isotropic Turbulence

We consider equilibrium statistics for high Reynolds number isotropic turbulence in an incompressible flow driven by steady forcing at the largest scale. Motivated by shell model observations, we develop a similarity theory for the inertial range from clearly stated assumptions. In the right variables, the theory is scaling invariant, but in traditional variables it shows anomalous scaling. We obtain the underlying probability density function, the scaling exponents, and the coefficients for the structure functions. An inertial range length scale also emerges.

physics.flu-dyn