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-   -   [SIMPLE VOF] (http://www.cfd-online.com/Forums/main/3610-simple-vof.html)

xazn June 15, 2001 04:56

[SIMPLE VOF]
 
Where can I find good paper about VOF using SIMPLE method ?

Kike June 15, 2001 05:24

Re: [SIMPLE VOF]
 
www.lmm.jussieu.fr/~zaleski/zaleski.html

Search into the "Publications on droplets and bubbles" Regards

Kike

My Name June 15, 2001 13:05

Re: [SIMPLE VOF]
 
Dude your group doesn't use VOF and simple method...

Or are you just advertising :)

My Name June 15, 2001 13:12

Re: [SIMPLE VOF]
 
Usually people use a projection method. Not a SIMPLE scheme for pressure correction. But some do use simple... Actually I use simple but I would warn everyone away from it... Its too ****** slow. At least if you use it make sure it is parallelized and multigrid. Anyway, Check out the recent papers from peric. I believe I have given a direct link to this before. Just do a search.

Kike June 18, 2001 06:21

Re: [SIMPLE VOF]
 
Dear "Name"

I perfectly know our code do not use SIMPLE and I am not advertising about anything.

At the address I gave you will find A LOT of references about VOF in which I am completely sure you will find (if you really search) references about VOF and SIMPLE.

It is allways better to know alternatives, specially if they are freely available for academic purposes. Now I am talking about our code VOF-PLIC Multigrid for two phases flow simulations. By the way, it is also parallelized in 2D and 3D.

I had made my PhD. using SIMPLEST in conjunction with VOF, applied to atomization and I will not warn anybody about it. Multigrid methods has also theirs drawbacks. Do not forget to mention them in your suggestions.

Regards

Kike


My Name June 18, 2001 14:07

Re: [SIMPLE VOF]
 
Multigrid's are acceleration techniques... SIMPLE is a technique used (designed for steady flows) to solve the incompressible momentum equations. Why would you even compare the two?

Yes, I agree multigrids have drawbacks... I.e. they may or may not perform better than single grid techniques, and they take up more space...

btw... you mean to say you are using a Fractional step-Projection method. And not to mention it is also semi-vectorized in 2D and 3D.

Now lets compare the time needed between Simple schemes vs. projection schemes in 3d for unsteady, multiphase flows... With or without multigrids or parallelized (acceleration techniques). The fact is that the SIMPLE schemes just do not compare for unsteady flows...

Maybe in 2-d someone might think of using a SIMPLE scheme if their problem is small and has no strong discontinuities.

Kike June 19, 2001 04:14

Re: [SIMPLE VOF]
 
Dear Name

Fromally I prefer to put Multigrid and and SIMPLE in the same bag: Numerical Integration Techniques. Each of them use a method to reduce the errors. The former is based on an iterative procedure and the later on coarse grid approximations.

In my oppinon it is not usefull to compare the techniques but the results of them applied to certain modelisation conditions (physical system to study, time vailable to obtain the results, hardware resources).

It is curious, the problem you avoid to solve with SIMPLE, I solved it during my PhD by this way: Two and Three Dimensional Gas-Liquid Interface Instabilities (density ratio 1/1000, kinematic viscosity ratio 10/1, velocity ratio 100/1, surface tension effects, interactions with solid edges, contact angle dynamics). Do you think they are no strong enough iscontinuities or singularities?

I have had good results (compared to experiments) by using SIMPLE and I have them also now by using Multigrids. Technique matter?, I don't think so.

Regards

Kike


My Name June 20, 2001 11:21

Re: [SIMPLE VOF]
 
I was talking about time. And here methods do matter. If I am iterating both momentum and pressure correction equations a multiple of times during one time step to converge with SIMPLE and the fractional step is only solved once... Do you see the difference??? (Again Multigrid is an acceleration technique which can be applied to both to pressure correction and the poisson solver so that extra time is irrelivant.)

I'm assuming that in your PhD you were solving grids of 150 cubed and with high surface tension effects in flows with predominant surface tension effects, which produce large pressure discontinuities?? (i.e. air and water).

Yes, the problem is solvable, but I certainly don't want to wait a couple of years for the solution with large grids!

--------------------------------------------------- To end this convesation I think it is fair to say that for your application SIMPLE was sufficient, however for my application it is not.

chinaduck May 23, 2014 11:30

Hello Kike,
Could you share your PhD thesis with me? Thanks, My email is:qukeforjc@hotmail.com.
Best,

Ke
Quote:

Originally Posted by Kike
;15425
Dear "Name"

I perfectly know our code do not use SIMPLE and I am not advertising about anything.

At the address I gave you will find A LOT of references about VOF in which I am completely sure you will find (if you really search) references about VOF and SIMPLE.

It is allways better to know alternatives, specially if they are freely available for academic purposes. Now I am talking about our code VOF-PLIC Multigrid for two phases flow simulations. By the way, it is also parallelized in 2D and 3D.

I had made my PhD. using SIMPLEST in conjunction with VOF, applied to atomization and I will not warn anybody about it. Multigrid methods has also theirs drawbacks. Do not forget to mention them in your suggestions.

Regards

Kike



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