Category 11: Shear Rate Equation#

The single boundary condition in this category is used to set a Dirichlet condition for the scalar shear rate equation. This differential equation is employed by the Phillips model for a suspension constitutive equation.


BC = SH NS <bc_id> <float1> [float2]

Description / Usage#


This boundary condition is used to set a Dirichlet condition for the scalar shear rate unknown field.

Description of the input parameters is as follows:


Name of the boundary condition (<bc_name>).


Type of boundary condition (<bc_type>), where NS denotes node set in the EXODUS II database.


The boundary flag identifier, an integer associated with <bc_type> that identifies the boundary location (node set in EXODUS II) in the problem domain.


Value at which the scalar shear rate unknown will be fixed on node set <bc_id>.


An optional parameter (that serves as a flag to the code for a Dirichlet boundary condition). If a value is present, and is not -1.0, the condition is applied as a residual equation. Otherwise, it is a “hard set” condition and is eliminated from the matrix. The residual method must be used when this Dirichlet boundary condition is used as a parameter in automatic continuation sequences.


An example of its used:

BC = SH NS 10 0.5

This boundary condition sets the scalar shear rate unknown to 0.5 on nodeset 10.

Technical Discussion#

The scalar shear rate unknown field is otherwise known as the second invariant of the rate of deformation tensor.