Elmer includes a level-set algorhitm for the solution of free surface problems. One canonical example of its use is the falling drop. Here it is assumed that the drop falls in the gravitational field through equally viscous fluid with significantly smaller density. The drop is held together by the surface tension. If the surface tension falls under some critical value the drop eventually breaks down. Here however, a steady state solution exists. In order to keep the drop from not falling outside the mesh the velocity of the frame is tuned by a simple feedback mechanism.

Still pictures refer to the converged steady state solution

• jpg, the shape of the drop
• jpg, the level-set function, i.e. the signed distance
• jpg, pressure field
• jpg, absolute velocity in the frame of the falling drop
• jpg, lateral velocity component in the frame of the falling drop
• jpg, the curvature of the drop
• jpg, the velocity field inside the drop

• drop.sif, command file
• square.grd, mesh file
• MyStuff.f90, user defined subroutine