A structure-based model for transport in stably stratified homogeneous turbulent flows

What is it about?

Turbulent transport in a stratified medium occurs in many engineering and geophysical applications. Examples include the transport of pollutants in the atmosphere and the transport of nutrients in marine flows. The large-scale turbulence eddies play a role in determining the transport of scalars (such as the nutrient concentration in the oceans), which therefore cannot be parametrized simply in terms of the scalar gradients alone. In this work, we present a new promising model that can capture many of the details of scalar transport in a stratified medium.

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Why is it important?

Event today, RANS models for the transport of scalars in a stratified medium face significant challenges, especially under conditions where the structural anisotropy of the turbulence plays a dominant mode in determining the primary modes of transport. The new model that is proposed here combines two innovative aspects: (1) the use of the structure-based approach in the transport equations, including a new set of scales equations and (2) the formulation of the closure as a particle-representation model.