Index

Kinematic condition
(for free surfaces and interfaces)

Ver: 2
 
 

DESCRIPTION

Data for moving boundaries or on moving interfaces are introduced.   OPTIONS
 
-1 Upper level menu
The current set-up is accepted
1 Surface tension
Allows to set the value of the surface tension coefficient.  Entering surface (or interfaccial) tension will require additional boundary conditions.
2 Boundary conditions
Allows to impose conditions on the position of the free surface,  possibly static contact angles if surface tension is present.
3 Normal force
Allows to set the value of the normal force applied on the free surface. This option is especially useful in blow moulding simulations.
4 Direction of motion
Allows to impose constraints (restrictions) on the directors defined along the free surface
5 Contact (Blow mold.)
Available in transient simulations only.
Allows to define contact problems : a free surface entering into contact with a solid mould.
6' Upwinding in the kinematic equation
Enable the use of upwinding in the kinematic equation. Use when the moving surface presents wiggles.
6" No upwinding in the kinematic equation
Disable the use of upwinding in the kinematic equation
7 Outlet (Inv. prediction)
When solving an inverse extrusion problem, allows to specify the intersection of the moving surface with the last section of the free jet.
8 Drag
Allows to study the effect of the air drag on axisymmetric fiber spinning
9 Contact lines (not available in the standard Polyflow package)
Special treatment of free surface-solid wall interactions
NOTES When large deformations of the interface are expected, an evolution must be considered. The recommended method is to switch to Evolution mode and to use "Evolution on moving boundaries",  in the Numerical Parameters menu;  another possible scheme is to introduce slip before the die lip, and to start an evolution on the "exslip" coefficient of the slip law. Indeed, fslip=0 corresponds to a free slip which induces no deformation, and "fslip" very large is equivalent to a no-slip boundary condition.

It is also possible to decrease the surface tension coefficient from a high to its nominal value. A high value reduces the free surface deformation at the beginning of the calculation.

Every sub-task which has (at least) one kinematic condition on its boundary must have a remeshing rule.

A single physical free surface or interface cannot belong to more than one sub-task.

  SEE ALSO