Two-dimensional, homogeneous, isotropic fluid turbulence with polymer additives

TL;DR

This study uses extensive direct numerical simulations to investigate how polymer additives affect two-dimensional homogeneous isotropic turbulence, revealing significant energy reduction, spectrum modification, and intermittency suppression.

Contribution

It provides the most comprehensive simulation analysis of polymer effects on 2D turbulence, including detailed energy and vorticity dynamics, and proposes new experimental directions.

Findings

Polymers reduce fluid energy, enstrophy, and palinstrophy.

Polymers modify the energy spectrum in different cascade regimes.

Polymers decrease small-scale intermittency and suppress high vorticity regions.

Abstract

We present the most extensive direct numerical simulations, attempted so far, of statistically steady, homogeneous, isotropic turbulence in two-dimensional fluid films with air-drag-induced friction and with polymer additives. Our study reveals that the polymers (a) reduce the total fluid energy, enstrophy, and palinstrophy, (b) modify the fluid energy spectrum both in inverse- and forward-cascade regimes, (c) reduce small-scale intermittency, (d) suppress regions of large vorticity and strain rate, and (e) stretch in strain-dominated regions. We compare our results with earlier experimental studies; and we propose new experiments.