A new eddy-viscosity model for large eddy simulation in helical turbulence

TL;DR

This paper introduces a novel eddy-viscosity model for large eddy simulation of isotropic helical turbulence, based on Kolmogorov's hypotheses, demonstrating improved accuracy in predicting energy and helicity evolution.

Contribution

A new single helical eddy-viscosity model is proposed, with a constant coefficient that can be dynamically determined, enhancing LES accuracy for helical turbulence.

Findings

The model accurately predicts energy and helicity evolution.

The statistical results are closer to DNS data.

The model outperforms dynamic Smagorinsky and mixed models.

Abstract

In isotropic helical turbulence, a new single helical model is suggested for large eddy simulation. Based on the Kolmogrov's hypotheses, the helical model is proposed according to the balance of helicity dissipation and the average of helicity flux across the inertial range, and the helical model is a kind of eddy viscosity model. The coefficient of the helical model is constant and can be also determined dynamically. Numerical simulations of forced and decaying isotropic helical turbulence demonstrate that the helical model predicts the energy and helicity evolution well. The statistical character of the helical model is closer to the DNS results.In a priori test, the energy and helicity dissipations of the helical model also show a good results. In general, the helical model has the advantage contrast with the dynamic Smogorinsky and mixed models.