Experiments on the Stability of Viscous Flow between Eccentric Rotating Cylinders

Abstract

The hydrodynamic stability of viscous flow between eccentric rotating cylinders has been studied experimentally. The ratio of the radii of the cylinders was 1 :2; several eccentricities were investigated. In the concentric configuration good agreement was achieved with previous experimental and theoretical work. Results obtained with the cylinders rotating in the same direction show that the effect of eccentricity can be stabilizing or destabilizing depending upon the speed of the outer cylinder and the amount of eccentricity. In the counterrotating case, a new flow phenomenon different from the usual vortex pattern was observed for large eccentricity.

Time-dependent patterns in counterrotating eccentric cylinders

“…Furthermore, their numerical results showed a shift of the mode transition points, or bicritical points, along the primary stability boundary towards smaller values of the outer cylinder to inner cylinder rotation frequency ratio as the eccentricity increases. Support for some of these results already existed in the experimental study by Versteegen and Jankowski [14] on the stability of viscous flow between eccentric cylinders when both cylinders rotate, especially for the case of corotating cylinders. However, their observations of counterrotating cylinders were limited to small values of the outer cylinder speed where the first bifurcation is to time-independent Taylor vortex flow.…”

Mass transport in a novel two‐fluid taylor vortex extractor

“…The alignment of the two cylinders is such that the gap on cithcr end is 0.882k0.017 cm ( & 2 % ) . This variation in the gap width is not expected to have a significant effect on the flow field based on the one-fluid analog (Koschmieder, 1976;Versteegen and Jankowski, 1969). Thc length of the annulus is I_ = 29.5 cm for an aspect ratio of L/d = 33.5.…”

Taylor‐Couette unit with a lobed inner cylinder cross section

“…A way to overcome this segregation, while keeping the main advantage of the TC flow, is to eliminate or reduce the low velocity (or low shear rate) regions in the TC flow so as to further narrow the shear rate distribution in the TC unit, thus improving mixing within and between the vortexes. One of the possible solutions is to locate eccentrically the inner cylinder of the TC unit25–29 to break the rotational symmetry of the flow, thus improving the mixing or shear rate distribution. Lopez and Marques30 proposed to rotate the inner cylinder at a constant angular velocity and simultaneously to rotate or move the outer cylinder at a velocity properly modulated in time.…”