Thanks Hrv. for your quick reply, some comments,
"Yes, I know exactly: the idea is that you perform an explicit flux limiting step before solving the VOF equation, based on availability of variable in the cells around the face. Thus, if the outgoing flux drives alpha below zero, it is limited; the same is the case with the incoming flux and upper limit."
Ok, I've caught this topic, but it's great for me you are confirming my suspicion. Now I can build upon this basis. The part of incoming and outgoing fluxes was not completely clear for me, thanks for the enlightment.
"The loop is executed 3 times; after clipping all the fluxes, the equation is solved explicitly and boundedness is preserved."
Aha, the loop is executed three times, this is some kind of lambda tune up I think... And about the clipping, its seem to be like a MinMod clipping or something similar (in the way of TVD schemes) but with an argument based on flux gradients in stead of values as is usual. Is that correct? Is it due the nonlinearity?
"Do you need to know more? To my knowledge, nobody ever bothered to write this up and the only person I know using similar tricks is Rob Kunz at Penn State."
Yes, maybe you know what theory is this limiter related to, at least loosely. My intention is to understand the limiter and work with it. My advisor is a big fan of High Resolution schemes and documenting too, then some docs will be generated open to the community. I'll contact to Rob Kunz. If you have some other tips, these will be greatly appreciated.
Best regards. Santiago.