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.

The velocity profiles for an infinite, cylindrical bearing are obtained by means of a small-eccentricity perturbation calculation. The modified Reynolds number appears as a parameter, and velocity profiles are presented for modified Reynolds numbers of 10−3, 10−2, 10−1, 1, 10, and 102. The most significant difference in the velocity profiles for the various Reynolds numbers is the appearance of components which are 90 deg out of phase with the film thickness at the larger values of the modified Reynolds number. The consequences of these components are discussed.

A large reduction in drag coefficient has been observed in certain external flows of aqueous solutions with high molecular weight polymer additives. A change in the near wake configuration is phenomenologically responsible for the drag reduction, but the underlying mechanism is presently unknown. An analogy to known phenomena in particulate suspensions is drawn which suggests nonuniform concentration of the polymer additive as an explanation. An analysis of the boundary layer on a sphere with varying viscosity was made to investigate the effect. The results indicate early transition to turbulence for concentration variations whose length scale is small compared with the momentum boundary layer thickness. Stabilization and delayed transition are indicated for thicker concentration layers. Observations are suggested for the thin concentration layers.

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