[an1710]

Hi,

I am using FLUENT to simulate open channel flow. The liquid (water) is set under motion by an impeller (paddlewheel), hence I define two cell zones: one zone encloses the impeller and is rotating (sliding mesh) and the remaining computational domain is stationary). My problem is modelled in 2D, assuming periodic boundaries. The free surface between the liquid-phase (water) and the air above, is tracked using VOF and the problem is solved transiently.

After approximately 1200 sec of simulation I inject 1000 inert particles of liquid-water material and use a UDF to track their position over time. The injection takes place in the liquid-phase only. The problem is that a considerable number of particles are passing through the free surface and move upwards from the liquid to the gas phase, which is physically inconsistent.

Any ideas why this is happening? Should massless particles help in solving the problem? Are there any known limitations regarding the use of DPM with periodic boundaries, VOF or sliding meshes?

Needless to say that any suggestion is highly appreciated :-)

Andreas