Dynamic feedback control through wall suction in shear flows

TL;DR

This paper explores a feedback control method using wall suction based on flow measurements to stabilize shear flows and reduce drag, combining theoretical and numerical approaches.

Contribution

It introduces a novel feedback control strategy that adjusts wall suction based on flow metrics to stabilize invariant solutions in shear flows.

Findings

Feedback control can stabilize flow states.

Wall suction reduces flow fluctuations.

Control strategy improves flow stability.

Abstract

Flow control is of interest in many open and wall-bounded shear flows in order to reduce drag or to avoid sudden large fluctuations that may lead to material failure. An established means of control is the application of suction through a porous wall. Here, we combine suction with a feedback strategy whereby the suction velocity is adjusted in response to either the kinetic energy or the shear stress at the bottom wall. The control procedure is then used in an attempt to stabilize invariant solutions and to carry out direct numerical simulations with a prescribed value of the friction coefficient.