Uniform shear viscosity Subject

When a neutrally buoyant, initially spherical drop is suspended in another liquid and subjected to shear or extensional stress, it deforms and then breaks up into smaller droplets. At low stress, in a steady, uniform shearing flow, the deformation can be expressed by means of three dimensionless parameters the viscosity ratio, the capillarity number, and the reduced time [1,24] ... 

When a fluid is flowing along a channel which has a uniform cross-section then the fluid will be subjected to shear stresses only. To define the flow behaviour we may express the fluid viscosity, rj, as the ratio of shear stress, r. 

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