Index
Define constraints on wall normals
Ver: 0
 

DESCRIPTION

Whenever a slip boundary condition is imposed along a wall,  a normal direction is computed in order to impose the constraint that the normal velocity vanishes.  By default,  this normal direction is unconstrained.  However,  there are situations where succesive iterations might lead to a variation in the normal direction that is incompatible with existing kinematic constraints.   This is the case,  for example,  in most coextrusion cases where imposing a slip model together with the integration of the kinematic condition can lead to deviations of the normal direction over the iteration steps.

In order to avoid this deviation,  it is possible to integrate kinematic limitations by imposing to zero some cartesian components of the normal.   For example in a coextrusion situation where Z is the (co)extrusion direction, the kinematic constraint becomes Nz=0.
 

  OPTIONS
 
 -1 
 Upper level menu
1
 Add constraint on X-Component of wall normal.
Specify that the X-component of the normal must be zero.
1
 Add constraint on Y-Component of wall normal.
Specify that the Y-component of the normal must be zero.
2
 Add constraint on Z-Component of wall normal.
Specify that the Z-component of the normal must be zero (3D)
EXAMPLES Coextrusion example in the example manual. SEE ALSO