Viscometric and Extensional Flows

Consider a steady simple shear flow with the kinematics given by u = yi3JC3, U2 = 0, Ms = 0 where the shear rate yj3 is a constant. This flow has the rate of deformation [Pg.13]

The generalized strain rate is y = yi3. There is a class of restricted flows called viscometric flows, which are motions equivalent to steady simple shearing. Tanner (2000) has show various viscometric kinematic fields where each fluid element is undergoing a steady simple shearing motion, with streamlines that are straight, circular, or helical. Each flow can be viewed as a relative sliding motion of a shear of inextensible material surfaces, which are called slip surfaces. [Pg.13]

Another important class of fluid flow is the extensional flow (or, elongational flow), which refers to flow where the rate of deformation tensor is diagonal. For an incompressible fluid, one can define the following form (Dealy 1994) [Pg.13]

For the uniaxial extensional flow, the generalized strain rate [Pg.13]

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