We have conducted a numerical studv of spherical Couette Vlow -the flow between differentiallv rotatin~ concentric spheres. When the qa D ratio o{(R2-RI)/RI (where R 1 and R 2 are the radii of the inner and outer spheres) is small, the flow near the e~uator resembles that between cylinders, the classic Tavlor-Couette ~roblem. As in Tavlor-Couette flow, when the angular momentum gradient, measur...

We show that turbulent "spirals" and "spots" observed in Taylor-Couette and plane Couette flow correspond to a turbulence-intensity modulated finite-wavelength pattern which in every respect fits the phenomenology of coupled noisy Ginzburg-Landau (amplitude) equations with noise. This suggests the existence of a long-wavelength instability of the homogeneous turbulence regime.

We study a large-scale instability in a sheared nonhelical turbulence that causes generation of large-scale vorticity. Three types of the background large-scale flows are considered, i.e., the Couette and Poiseuille flows in a small-scale homogeneous turbulence, and the "log-linear" velocity shear in an inhomogeneous turbulence. It is known that laminar plane Couette flow and antisymmetric mode...

This study focuses on the dynamics of the Taylor-Couette Vortex Flow (TVF) in a photo-bioreactor in which CO2 is changed to O2 with high efficiency by the photosynthesis ability of micro algae. Stirring by means of a screw propeller is generally used for a simple agitation. However, the problem is that there exists a very high shearing flow region just near the propeller, which causes the destr...

Linear dichroism (LD) can be used to study the alignment of absorbing chromophores within long molecules. In particular, Couette flow LD has been used to good effect in probing ligand binding to DNA and to fibrous proteins. This technique has been previously limited by large sample requirements. Here we report the design and application of a new micro-volume Couette flow cell that significantly...

The threshold amplitude for subcritical transition in Poiseuille and Couette ows is investigated. For Poiseuille ow we present examples where the threshold scales like R ?7=4 for 1500 R 5000, where R is the Reynolds number. For Couette ow we present an example where the threshold scales like R ?5=4 for 500 R 2000.

A recent Letter [R. Hollerbach and G. Rüdiger, Phys. Rev. Lett. 95, 124501 (2005)] has shown that the threshold for the onset of the magnetorotational instability in a Taylor-Couette flow is dramatically reduced if both axial and azimuthal magnetic fields are imposed. In agreement with this prediction, we present results of a Taylor-Couette experiment with the liquid metal alloy GaInSn, showing...

This paper describes an investigation, which uses a torquemeasurement technique, of effects of axial flow on the stability of Taylor-Couette flow. Two radius ratios, 0.846 and 0.956, are used. The preliminary results show that the critical Taylor number for the onset of Taylor vortices increases monotonically with the Reynolds number of the axial flow and asymptotes to a constant value. Althoug...

We consider the Taylor-Couette problem in an infinitely extended cylindrical domain. There exist modulated front solutions which describe the spreading of the stable Taylor vortices into the region of the unstable Couette flow. These transient solutions have the form of a front-like envelope advancing in the laboratory frame and leaving behind the stationary, spatially periodic Taylor vortices....