Iterative control of G\"{o}rtler vortices via local wall deformations

TL;DR

This paper proposes a control method using local wall deformations to suppress G"{o}rtler vortices, demonstrating effectiveness in reducing vortex growth and wall shear stress through numerical simulations.

Contribution

The study introduces a novel control strategy employing local wall deformations and a proportional control algorithm to mitigate G"{o}rtler vortices.

Findings

Control effectively reduces vortex energy growth.

Wall shear stress is minimized by the control algorithm.

Numerical results confirm the method's efficacy.

Abstract

G\"{o}rtler vortices develop along concave walls as a result of the imbalance between the centrifugal force and radial pressure gradient. In this study, we introduce a simple control strategy aimed at reducing the growth rate of G\"{o}rtler vortices by locally modifying the surface geometry in spanwise and streamwise directions. Such wall deformations are accounted in the boundary region equations (BRE) by using a Prandtl transform of dependent and independent variables. The vortex energy is then controlled via a classical proportional control algorithm for which either the wall-normal velocity or the wall shear stress serves as the control variable. Our numerical results indicate that the control algorithm is quite effective in minimizing the wall shear stress.