[anthi]

Hello.

I am trying to model a (water - air) tank using a two phase model in CFX.

In most papers the VOF model is used which is unfortunately only available in Fluent. Since I am a user of CFX I tried to model the tank using the homogeneous model - Free surface model based on a tutorial. However, according to documentation this is a single phase transport equation and all the volocities are "bulk" and not phasic velocities.

1.) Does anybody know which are the basic differences between VOF and homogeneous model? Papers are very limited about homogeneous model. I would also appreciate any available links of papers regarding the homogeneous free surface model.

2.) Is it more appropriate to use homogeneous or inhomogeneous model in CFX?

3.) Can homogeneous or inhomogeneous model predict the waves' development at the surface of the tank or should I better try to model the tank in Fluent?

Thanx in advance.

[ghorrocks]

The difference between VOF and CFX's homogeneous approach is subtle. So subtle that I do not know it . Fluent does have a wider range of VOF differencing schemes including surface reconstruction ones, but the underlying model is so close to CFX as to be the same to my knowledge.

Homogeneous means a single velocity field is shared between all phases. Inhomogeneous means each phase has its own velocity field. For a pure free surface model where you directly resolve the surface then use homogeneous. For a mixed free surface/bubble model (eg surf at the beach where you have both a clear free surface and a bubbly/foamy flow) then consider the inhomogeneous model.

Both homo and inhomo can predict wave development. So can Fluent. Both CFX and Fluent can do this.

[anthi]

Thanx a lot for the useful guidelines!