Secondary flow cellular

Secondary flows are of particular concern in the controlled stress instruments which usually employ a rotating inner cylinder, in which case inertial forces cause a small axisymmetric cellular secondary motion ( Taylor vortices). The dissipation of energy by these vortices leads to overestimation of the torque. The stability criterion for a Newtonian fluid in a narrow gap is... 

Secondary flows in the Couette geometry have been well studied following Taylor s classic work (1923). Vfith the inno- cylinder rotating at some speed, inertial forces cause a small axisymmet-ric cellular secondary motion known as Taylor vortices or Taylor cells. These dissipate energy and cause an increase in the measured torque. Some data from Denn and Roisum (1969) for a glycerin-water solution are shown in Figure 5.3.8. For Newtcmian fluids and narrow gaps, the criterion for stability is... 

Sometimes a distinction is made between cellular growth and dendritic growth. In cellular growth the primary arms extend into the liquid but there are no secondary dendrite arms. Figure 10.17 illustrates this. In either case, however, primary arms extend in the direction of heat flow. The tendency to cellular and... 

Liver biopsies have been performed in some patients with chronic vitamin A intoxication. Perisinusoidal fibrosis and massive accumulation of lipid-storing cells were found. Impairment of blood flow by perisinusoidal fibrosis probably resulted in secondary alterations in hepato-cytes, including cellular atrophy and formation of cytoplasmic bullae. Histological examination also showed central vein sclerosis and focal congestion associated with perisinusoidal storage. The vitamin A concentration in the liver was increased (40-42). 

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