3d VOF troubles...

Mac

Hi there,

I'm having trouble making my model produce anything worthwhile at all... bare in mind i'm quite new to CFD in general...

i have water flowing through a pipe into an open topped vessel (approx cubic, with 2m side length), the vessel then tapers down into an rectangular open channel about 1m wide and 15m long. i want to find turbulence caused in channel by changing the geometry of the vessel.

have modelled with the following settings so far:

- VOF, 3d, open channel, gravity on, unsteady - phases are air (primary) and water

- model has mass flow inlet for pipe entrance, at 50 l/s - open top of vessel and channel has gauge pressure set to 0 - outlet face set to pressure outlet with free surface at 0.5m - all other surfaces are walls

- i've patched water volume fraction to 0.5

i've tried to create an iso-surface after initialising so i can view the free surface, but i just get a mess of dots spread evenly on the existing surfaces, not a clean interface surface within the volume... does that mean something's wrong?

any suggestions for iteration/time step values to try? i really have no idea.