Rotating inclined cylinder and the effect of the tilt angle on vortices

TL;DR

This study numerically investigates vortex configurations in a rotating, tilted cylinder, revealing how tilt angle influences vortex stability, flow patterns, and turbulence, with potential experimental applications.

Contribution

It introduces a numerical analysis of vortex behavior in tilted rotating cylinders, highlighting the impact of tilt angle on vortex stability and turbulence formation.

Findings

Vortices tend to align along the cylinder axis at small tilt angles.

Tilt-induced axial flow can trigger Ostermeier-Glaberson instability.

Inclined cylinders can sustain long-lasting, adjustable turbulence.

Abstract

We study numerically some possible vortex configurations in a rotating cylinder that is tilted with respect to the rotation axis and where different numbers of vortices can be present at given rotation velocity. In a long cylinder at small tilt angles the vortices tend to align along the cylinder axis and not along the rotation axis. We also show that the axial flow along the cylinder axis, caused by the tilt, will result in the Ostermeier-Glaberson instability above some critical tilt angle. When the vortices become unstable the final state often appears to be a dynamical steady state, which may contain turbulent regions where new vortices are constantly created. These new vortices push other vortices in regions with laminar flow towards the top and bottom ends of the cylinder where they finally annihilate. Experimentally the inclined cylinder could be a convenient environment to create long lasting turbulence with a polarization which can be adjusted with the tilt angle.