The basic steps for setting up an integral viscoelastic flow are as follows:
Create a sub-task for the integral viscoelastic flow problem.
Create a sub-task
Select the appropriate problem type from the Create a sub-task menu.
Integral viscoelastic isothermal flow problem
or
Integral viscoelastic non-isothermal flow
problem
When prompted, specify a name for the sub-task.
Specify the region where the sub-task applies.
Domain of the sub-task
Define the material properties.
Material data
Select the integral viscoelastic model to be used and set the related parameters. See Choosing the Integral Viscoelastic Model for guidelines on choosing an appropriate model.
Integral Viscoelastic models
The KBKZ model is the default Type of model listed at the top of the menu. To use the Doi-Edwards model, select Switch to Doi-Edwards Model.
Switch to Doi-Edwards Model
To switch back to the KBKZ model, select Switch to KBKZ Model
Switch to KBKZ Model
If you want to perform the simulation for the generalized Newtonian model that has the same shear viscosity as the selected viscoelastic model (using Equation 11–55), choose Switch to Generalized Newtonian Flow.
Switch to Generalized Newtonian Flow
As mentioned in Equivalent Generalized Newtonian Models, the solution for the equivalent generalized Newtonian model can be compared with the viscoelastic model results to determine the relative importance of elasticity on the behavior of the flow being modeled.
To switch back to the selected viscoelastic model, select Switch to Viscoelastic Model.
Switch to Viscoelastic Model
Specify the range of relaxation modes for the model.
Modify the spectrum
Specify how you want to define the relaxation modes. By default, the relaxation spectrum is defined by means of (viscosity, relaxation time) pairs. To specify (relaxation force, relaxation time) pairs, select Switch to Elasticity - Relaxation time data.
Switch to Elasticity-Relaxation time
data
To switch back to the (viscosity, relaxation time) pairs, select Switch to Viscosity - Relaxation time data.
Switch to Viscosity-Relaxation time
data
(for KBKZ model only) Specify the number of relaxation modes. You can define up to 8 modes.
Number of relaxation modes
Since the Doi-Edwards model performs a summation over an infinite number of relaxation modes (see Equation 11–47), the specification of an explicit number of modes is irrelevant.
Specify the data pairs, either for all relaxation modes or for just a selected few.
To specify data pairs for all modes, select Modify the whole spectrum.
Modify the whole spectrum
When prompted, enter the requested data.
To specify data pairs for a subset of the modes, select Modify some values of the spectrum.
Modify some values of the
spectrum
Then select each mode to be modified and enter the requested data when prompted.
When you are satisfied with all settings, select No modification to accept them.
(for KBKZ model only) Specify the damping function.
Modify the damping function
Select Lodge-Maxwell model (the default) for no damping. No further inputs are required.
Select Reversible Papanastasiou-Scriven model to use the reversible version of Equation 11–52. The inputs for this model are
in Equation 11–52 and 
in Equation 11–54. Select Irreversible Papanastasiou-Scriven model to use the irreversible version of Equation 11–52. The inputs are the same as for the reversible version.
Select Reversible Wagner model to use the reversible version of Equation 11–53. The inputs for this model are
in Equation 11–53 and 
in Equation 11–54. Select Irreversible Wagner model to use the irreversible version of Equation 11–53. The inputs are the same as for the reversible version.
See Choosing the Integral Viscoelastic Model for more information about setting parameters for the damping function.
Specify the ratio of the normal-stress differences (for KBKZ model only).
Ratio of the diff. of Norm. stresses
(N2/N1)
This value is used in Equation 11–51 to compute the value of
that appears in Equation 11–50. Specify the additional viscosity.
Modification of the additional
viscosity
To include the purely viscous component of the extra stress tensor (
in Equation 11–2), set 
(the additional viscosity) to a nonzero
value. Specify the evolutive viscosity.
Management of the evolutive viscosity
See Setting the Evolutive Viscosity for details.
Define the numerical integration scheme for the viscoelastic model.
Numerical integration
See Additional Strategies for Convergence for details.
For nonisothermal flows, specify the temperature shift (
in Equation 11–46).
Temperature dependence
You can specify no temperature dependence, or select the Arrhenius law, Arrhenius approximate law, or WLF law. See Temperature-Dependent Viscosity Laws and Problem Setup for details.
If inertia, heat convection, or natural convection are to be taken into account in the calculation, define the density, inertia terms, and gravity. (By default, density is equal to zero, inertia terms are neglected, and gravitational acceleration is equal to zero.) For many processing applications, the Reynolds number is so low that inertia terms can safely be neglected. Even in the absence of inertia terms, however, it may be necessary to assign nonzero value for density and gravitational acceleration, since they influence heat capacity and buoyancy forces.
Set the density.
Density
Select Modification of density and enter a new value.
Enable the inertia terms in the momentum equations.
Inertia terms
Select Inertia will be taken into account to enable the inertia terms. (To disregard the inertia terms, you can select Inertia will be neglected, the default setting.) Note that the option to take inertia into account will not be available if the density is equal to zero. You will need to specify a nonzero density first, in order to enable the inertia terms.
Set the gravitational acceleration.
Gravity
Select Modification of gx and set the gravitational acceleration in the
direction. Repeat for the 
component.
Set any other appropriate material properties. For nonisothermal flows, for example, see Problem Setup for instructions.
Define the flow boundary conditions.
Flow boundary conditions
See Boundary Conditions for details.
For nonisothermal flows, define the thermal boundary conditions.
Thermal boundary conditions
See Boundary Conditions and Problem Setup for details.