Instabilities in magnetized spherical Couette flow

taylor-couette flow instabilities in journal bearings

in industry, flow instabilities are important in journal bearings at high rotational speeds. for inviscid flows between two rotating coaxial cylinders, an instability criterion was introduced by taylor-couette. however, viscosity may play as stabilizer or destabilize in such flows. in this work, stability theories were reviewed for two coaxial rotating cylinders. then, flow instability patterns...

Pinch instabilities in Taylor-Couette flow.

The linear stability of the dissipative Taylor-Couette flow with an azimuthal magnetic field is considered. Unlike ideal flows, the magnetic field is a fixed function of a radius with two parameters only: a ratio of inner to outer cylinder radii, eta, and a ratio of the magnetic field values on outer and inner cylinders, muB. The magnetic field with 0<muB<1/eta stabilizes the flow and is called...

Convective Instabilities in Plane Couette Flow

Zonal shear and super-rotation in a magnetized spherical Couette-flow experiment.

We present measurements performed in a spherical shell filled with liquid sodium, where a 74-mm-radius inner sphere is rotated while a 210-mm-radius outer sphere is at rest. The inner sphere holds a dipolar magnetic field and acts as a magnetic propeller when rotated. In this experimental setup called "Derviche Tourneur Sodium" (DTS), direct measurements of the velocity are performed by ultraso...

Driven inertial waves in spherical Couette flow.

Dynamo action in the cores of planets and stars gives rise to their magnetic fields. We explore spherical Couette flows in liquid sodium as a laboratory model of the Earth’s core. Below, we image various spatiotemporal magnetic-field modes present in spherical Couette flows. Our apparatus is comprised of two independently driven rotating spheres, radii 20 and 60 cm, with sodium filling the gap ...