Can STAR-CD simulate air injecting thru. a tube to water in a tank? I believe this is a problem of fluid interaction or fluid mixing, not multiphase flow.

If connot, which CFD code can handle this?

Thanks, HW

since you have 2 phases: air & water, it is a multiphase flow problem

[ping]

The standard VOF model in either STAR-CD or STAR-CCM+ will handle this case - you need to keep the cell sizes down in the order of the tube size and resulting bubbles to capture the bubbles well. Otherwise try the Eulerian-Eulerina model.