Modelling of the subgrid scale wrinkling factor for large-eddy simulation of turbulent premixed combustion

TL;DR

This paper introduces a new model for the unresolved wrinkling factor in LES of turbulent premixed combustion, based on a power-law dependence and an original strain rate expression, validated against experimental data.

Contribution

It presents a novel model for the subgrid scale wrinkling factor that accounts for viscous effects, finite Reynolds numbers, and is consistent with known asymptotic behaviors.

Findings

Model accurately predicts the wrinkling factor across different regimes.

Incorporates finite Reynolds number effects into the wrinkling factor.

Validated against experimental filtered database.

Abstract

We propose a model for assessing the unresolved wrinkling factor in LES of turbulent premixed combustion. It relies essentially on a power-law dependence of the wrinkling factor to the filter size and an original expression for the active corrugating strain rate. The latter is written as a product of an efficiency function which accounts for viscous effects and the kinematic constraint of Peters, by a recent expression for the turbulent strain intensity. Yields functional expressions for the fractal dimension and the inner cut-off length scale, the latter being (i) filter-size independent and (ii) consistent with the Damk\"ohler asymptotic behaviors at both large and small Karlovitz numbers. A new expression for the wrinkling factor which incorporates finite Reynolds numbers effects is further proposed. Finally, the model is successfully assessed on an experimental filtered database.