Coarse-grained description of a passive scalar
arXiv:nlin/0602061 · doi:10.1080/14685240600779388
Abstract
The issue of the parameterization of small-scale dynamics is addressed in the context of passive-scalar turbulence. The basic idea of our strategy is to identify dynamical equations for the coarse-grained scalar dynamics starting from closed equations for two-point statistical indicators. With the aim of performing a fully-analytical study, the Kraichnan advection model is considered. The white-in-time character of the latter model indeed leads to closed equations for the equal-time scalar correlation functions. The classical closure problem however still arises if a standard filtering procedure is applied to those equations in the spirit of the large-eddy-simulation strategy. We show both how to perform exact closures and how to identify the corresponding coarse-grained scalar evolution.
22 pages; submitted to Journal of Turbulence
References in corpus (11)
- Particles and fields in fluid turbulence
- ANOMALOUS SCALING OF THE PASSIVE SCALAR
- Anisotropy in Turbulent Flows and in Turbulent Transport
- Normal and Anomalous Scaling of the Fourth-Order Correlation Function of a Randomly Advected Passive Scalar
- Anomalous Scaling Exponents of a White-Advected Passive Scalar
- Intermittency in passive scalar advection
- Eddy diffusivities in scalar transport
- Fronts in passive scalar turbulence
- Passive scalar anisotropy in a heated turbulent wake: new observations and implications for LES
- Multiple-scale analysis and renormalization for pre-asymptotic scalar transport
- Large-Eddy Simulation closures of passive scalar turbulence: a systematic approach