Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

fluid instabilities in comsol

Please login with a confirmed email address before reporting spam

does anybody have tried [ or succeeded] to model Rayleigh taylor instabilities at the interface of 2 different moving fluid?
The case i need to investigate is 2 fluids in a cylindrical pipe pushed by a pressure pulse.
the "less viscous and less dense fluid pushing the highly viscous and denser fluid].
The shape of the interface between the fluids and its evolution over time [ instability growth rate] is the output of the study

If yes, can you then tell me how you did it and if you stumbled what was the problem?
If you could post some models or point existing relevant references, it will be obviously wonderful too :-)

I am fully aware of the difficulty of the problem but want to see if I can use comsol before moving toward more specialized tool.

I have looked in the model library and the documentations but did not found anything obviously relevant...

Thanks for your input
JF

2 Replies Last Post 2010年4月22日 GMT-4 11:58

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2010年4月22日 GMT-4 02:58
Hi Jean

Are you dealing with two-phase flow? If you are using level set/phase field module? I beleive this is something to do with adding BC in PDE (to supplement the existing BC: initial fluid interface). I came to know that COMSOL V4.0 may have some additional features in its CFD module releasing this June.
By the way, are you able to model using two-fluid (euler-euler approach), this could give much flexibility in defining interface physcis on each fluid. I am also involved in a similar role of two-phase modelling and found a very little help in the current version of COMSOL.

Regards
Naveed
Hi Jean Are you dealing with two-phase flow? If you are using level set/phase field module? I beleive this is something to do with adding BC in PDE (to supplement the existing BC: initial fluid interface). I came to know that COMSOL V4.0 may have some additional features in its CFD module releasing this June. By the way, are you able to model using two-fluid (euler-euler approach), this could give much flexibility in defining interface physcis on each fluid. I am also involved in a similar role of two-phase modelling and found a very little help in the current version of COMSOL. Regards Naveed

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2010年4月22日 GMT-4 11:58
Hi Naveed,
I have not written anything sofar.. i need to study RT instability growth rate a the interface of two fluids of very different viscosity in ythe unstable configuration, that is the less viscous pushing the mroe viscous and try to decide wether or not it is worth spending time on this problem with comsol vs. using mroe specifics cfd code.
so my question is to know if there is any experience [ good or bad...] in the comsol community I could benefit in deciding upon the best use of my time...
jf
Hi Naveed, I have not written anything sofar.. i need to study RT instability growth rate a the interface of two fluids of very different viscosity in ythe unstable configuration, that is the less viscous pushing the mroe viscous and try to decide wether or not it is worth spending time on this problem with comsol vs. using mroe specifics cfd code. so my question is to know if there is any experience [ good or bad...] in the comsol community I could benefit in deciding upon the best use of my time... jf

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.