The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear.
12.
For engineering purposes, the wind gradient is modeled as a simple shear exhibiting a vertical velocity profile varying according to a power law with a constant exponential coefficient based on surface type.
13.
Simple shear with the rate \ dot \ gamma is the combination of pure shear strain with the rate of \ dot \ gamma and rotation with the rate of \ dot \ gamma:
14.
Important examples of simple shear include laminar flow through long channels of constant cross-section ( Poiseuille flow ), and elastomeric bearing pads in base isolation systems to allow critical buildings to survive earthquakes undamaged.
15.
These findings indicate that uniform pure shear is not in effect in the PRMB . While some have suggested that the PRMB is on the upper plate in a simple shear model, findings in the conjugate margin, the Dangerous Grounds, also dispute this model.
16.
Thus, the upper-convected Maxwell model predicts for the simple shear that shear stress to be proportional to the shear rate and the first difference of normal stresses ( T _ { 11 }-T _ { 22 } ) is proportional to the square of the shear rate, the second difference of normal stresses ( T _ { 22 }-T _ { 33 } ) is always zero.
