This constraint is primarily used to dampen velocity fluctuations in the start-up phase of simulations. When the local velocity exceeds the user-supplied maximum value a sink term is activated in the affected region to lower the velocity to the limiting value.

Properties🔗

Additional reporting is provided for the number of cells being damped, and as a percentage of cells over the complete mesh.

When active, this constraint manipulates the system of equations. Users should ensure that it is not active when the case is converged (steady-state) or during the period of interest (transient) to ensure that its presence does not pollute the results.

Usage🔗

velocityDamping
{
    type            velocityDampingConstraint;
    selectionMode   all;
    UMax            200;
}

Further information🔗

Tutorials

• none

Source code

• $FOAM_SRC/fvOptions/constraints/derived/velocityDampingConstraint