Dispersed Fibers Change the Classical Energy Budget of Turbulence via Nonlocal Transfer
Stefano Olivieri, Luca Brandt, Marco Edoardo Rosti, Andrea Mazzino
Abstract
The backreaction of dispersed rigid fibers to turbulence is analyzed by means of a state-of-the-art fully coupled immersed boundary method. The following universal scenario is identified: turbulence at large scales looses a consistent part of its kinetic energy (via a Darcy friction term), which partially reappears at small scales where a new range of energy-containing scales does emerge. Large-scale mixing is thus depleted in favor of a new mixing mechanism arising at the smallest scales. Anchored fibers cause the same backreaction to turbulence as moving fibers of large inertia. Our results thus provide a link between two apparently separated realms: the one of porous media and the one of suspension dynamics.