Contact Angle
This feature specifies the contact angle between the free surface and a solid wall. The Contact Angle feature is a subfeature to, and added under a Free Surface feature.
Contact Angle
Select an option from the Specify contact angle list — Directly (the default) or Through Young’s equation.
•
For Directly enter a Contact angle θw (SI unit: rad). The default is π/2.
•
For Through Young’s equation enter values or expressions for Phase 1-Solid surface energy density γs1 (SI unit: J/m2) and Phase 2-Solid surface energy density γs2 (SI unit: J/m2).
This condition applies forces on the wall that balance the surface tension for the prescribed contact angle.
For laminar flow, the Contact Angle node should be used on edges or points where a Navier Slip wall boundary condition is applied adjacent to the free surface. In this case, the Navier Slip condition is required for the contact line to move along the wall.
The representation of the contact angle is dependent on the mesh resolution in the region where the fluid-fluid interface attaches to the wall. If, during the simulation, the contact angle is found to fluctuate around a given value, this indicates that the resolution needs to be improved. This can for example be achieved by adding more mesh boundary layers on the wall.
The moving mesh boundary condition must be compatible with the motion of the wall for the problem to have a valid solution.