Bruno Jouault | Searcharxiv

arXiv1999

Indistinguishable multiplier statistics of discrete and continous turbulent cascade models

The multiplier statistics of discrete and continuous nonconservative multiplicative cascade models, employed to describe the energy cascade in fully developed turbulence, is investigated. It is found to be indistinguishable due to small-scale resummation and restoration of spatial homogeneity. Only the subclass of positively skewed weight distributions, associated to the cascade generator, qualifies to describe observed unconditional as well as conditional multiplier distributions qualitatively; popular log-Poisson and log-stable weight distributions do not share this property.

chao-dyn↗

arXiv1998

Multiplier phenomenology in random multiplicative cascade processes

We demonstrate that the correlations observed in conditioned multiplier distributions of the energy dissipation in fully developed turbulence can be understood as an unavoidable artefact of the observation procedure. Taking the latter into account, all reported properties of both unconditioned and conditioned multiplier distributions can be reproduced by cascade models with uncorrelated random weights if their bivariate splitting function is non-energy conserving. For the alpha-model we show that the simulated multiplier distributions converge to a limiting form, which is very close to the experimentally observed one. If random translations of the observation window are accounted for, also the subtle effects found in conditioned multiplier distributions are precisely reproduced.

chao-dyn↗