Capilliary action (surface tension) effects are an extremely important consideration when modeling time transient fluidic problems involving free surfaces, such as ink jet printer nozzles. The ANSYS Multiphysics free surface capability uses Volume of Fluids (VOF) technology in which the fluid moves through the mesh, hence no mesh morphing is required.
In a Volume of Fluid (VOF) analysis, an advection algorithm is used for the volume fraction (VFRC) to track the evolution of the free surface. For the dynamic behavior at the interface between a gas and liquid, we use a continuum surface force (CSF) method to model the surface tension. Surface tension is an inherent characteristic of material interfaces. It is a localized surface force acting on the interface.
The ANSYS VOF capability is available for quadrilateral elements for two dimensional planar or axisymmetric analyses. The surface tension material properties can be temperature dependent. Contour plots of the fluid boundaries and pressure distributions within the fluid are available.
Axisymmetric model rotated to provide a 3-D visualization of an inkjet printer nozzle droplet formation.