Rotating Couette Flow Research Articles

Stability of Rotating Couette Flow. II. Comparison with Numerical Results

Measurements have been made of the onset of instability in rotating Couette flow in order to check some recent numerical results. The case of a very wide gap, a medium gap, and a very narrow clearance ratio have been studied. The accuracy of the results is about ± 2%. The present data and other values available in the literature are compared with the computations of different investigators. With a few exceptions the agreement is found to be excellent. End effects are described and their relative importance is discussed. Methods of scaling the results are evaluated. A simple formula is presented for calculating the onset value when only the inner cylinder rotates.

Stability of Rotating Couette Flow. I. Asymmetric Waveforms

Experiments are described which show that the waveform at onset of instability in rotating Couette flow may be asymmetric about the rotational axis. Thus, the prediction of Krueger, Gross, and DiPrima is verified. The waveforms have been observed using various cylinders with gap ratios ranging from 0.20 to 0.96. The data covers the complete range where simple asymmetric modes occur. A complicated transient motion is described which leads to the spiral waveforms observed at onset. All predictions of Krueger et al. are in accord with experiment and previous experimental work can be reconciled with both the theory and the present observations. A waveform which is subharmonic in the axial direction is also studied.

Rotating Couette Flow of a Binary Liquid Mixture

Impulsively started, rotating Couette flow of a binary, perfect solution is discussed for the purpose of exhibiting possible multifluid phenomena. It is shown that inhomogeneity due to baro‐diffusion can give rise to phenomena which are commonly thought of as rheological effects.

Wave Motion in a Rotating Couette Flow of a Viscous Fluid

Wave Motion in a Rotating Couette Flow of a Viscous Fluid

Wave Motion in a Rotating Couette Flow of a Viscous Fluid

With the assumption of non-divergence horizontal flow, a certain class of solutions of the nonlinear hydrodynamic equations are obtained for a viscous Couette flow on an earth whose variation of Coriolis parameter with latitude is constant. These solutions yield waves of transient type, of which the amplitude, wave velocity, and the inclination of the trough and ridge lines vary with time.
 For Couette flow with both lateral and vertical velocity-shears, the vertical profile of the amplitude of the waves can either be exponential in z or independent of z, whereas for Couette flow with lateral velocity-shear only it permits to be independent of z, a sinusoidal function, or a hyperbolic sine or cosine of z. These waves will eventually disappear in a Couette flow regardless the fluid is viscous or not, although under certain conditions waves may be amplified within a certain time interval.
 Pressure field, geostrophic deviation, meridional transports of energy and westerly momentum are obtained for such a flow system. For reasonable values of the constants for atmospheric systems, geostrophic deviation can be as high as one order magnitude smaller than the actual wind speed.