Unfortunately Elmer does not have much capabilities when it comes to multiphase flows. You can have a number of passive components sitting on the flow, and maybe even have the material properties depend on the concentration. However, if the velocities of the phases differ this is not a suitable strategy as you correctly state.Greetings,
I would like to model liquid flow driven by bubbles -- not a few, as can
be done with level set, but hundreds or thousands, enough to use a
continuum method. The bubbles and the liquid need to have their own
separate velocity fields which are of course coupled to each other.
I don't see a suitable existing model in the Elmer Models Manual, and
can't think of a way to use say advection-diffusion, as the bubbles
might diffuse slightly, but really need to move in the direction given
by (bubble size-dependent) buoyancy plus drag due to the liquid flow.
Is there a way to do this with Elmer as it is, or would it require a new
model?
Thanks,
-Adam
The remedy would be to have separate equations for the different phases and also handle the interaction between the them. This is a considerable task considering that there is a plethora of different formulations that one can make. To my knowledge there is no ongoing work to implement true multiphase flow equations.
Apart from the continuum approach (Eulerian) one can also take a particle approach (Lagrangian). This would be fitting particularly if there is a large different between the velocity of the bubbles and the fraction of bubbles remains rather low (<10%). A Lagrangian particle tracker would allow you to follow the path of a number of particles (real or statistical). For this kind of particle tracking there has recently been some requests so we are considering implementing it. Modeling of multiphase flows could take use of it even though it needs some additional features for consistancy. Maybe this kind of approach could be feasible in your case?
BR, Peter