[TullyK]

Dear all,

I am investigating the various models capable of accounting for air entrainment in spillway flows and similar. Currently I am focusing on three pieces of software: FLOW-3D, OpenFOAM and Ansys CFX/Fluent.

It would seem that FLOW-3D has the most comprehensive offering, with two different models capable of modelling

a) small amounts of air entrainment with no alteration to the liquid properties.

b) large amounts of air entrainment by means of a density variable, which allows for buoyancy effects to be taken into account but, as far as I can tell, the flow is still calculated as if it were a single phase.


This option b) would seem acceptable for modelling spillway flows however I would still like to establish what options there are in the other two programs.

I have come across numerous accounts of people modelling air entrainment in OpenFoam, usually using the interFoam solver. Given that interFoam is described as a "solver for 2 incompressible fluids capturing the interface using a VOF method. No turbulence model is used." (Hemida, 2008), I assume air entrainment models using this solver are using a different approach to the FLOW-3D models.

Is anyone able to shed some light on the methods available in OpenFOAM for air entrainment?


I have thus far found no clear accounts of Ansys software being used to model air entrainment but would like to hear from anyone who has.

Thanks in advance for any help you can offer.

Regards,

Tully




Reference:

OpenFOAM tutorial: Free surface tutorial using interFoam and rasInterFoam
Hassan Hemida, 2008
http://www.tfd.chalmers.se/~hani/kur...Hemida_VOF.pdf