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mike April 12, 2006 12:13

dye simulation-followup
Hi Everybody, I still have problem with dye simulation. I used additional variable approach as you suggested. Here are my problems;

I am defining the dye as scalar additional variable specific with no units. I am setting expert parameters solve fluid, turbulence and volumefrc f (is this correct?). Then I am creating a source point with constant mass flow rate. I did not understand how CFX solves this since I am defining it without units and then I am giving constant mass flow rate, and it is solving!!

By the way, I am using steady state solution as inital conditions. And writing transient results in output file. During post process, I am creating isosurface and animating it. But the animation doesnot look like what I want.

Could you please guide me on this problem? Also I posted a question about mesh generation yesterday. I would be very glad if you could enlighten me for any of these issues.

Thanks alot,


mike April 12, 2006 13:34

Re: dye simulation-followup
Also, when I am doing quick animation, first evolutions takes place very slowly and the rest is done very quickly even you cant see it. Why is this happening? Do you have any ideas? Instead, it should be vice versa, since I am injecting dye in an area where the bulk fluid motion is very fast. Thanks alot, Mike

Glenn Horrocks April 12, 2006 18:07

Re: dye simulation-followup

Get rid of the expert parameters. That's the first suggestion. Most of the time the defaults are fine and it automatically knows which equations to turn on and off.

Glenn Horrocks

mike April 13, 2006 08:36

Re: dye simulation-followup
Thanks Glenn, I will try it now. One question, this isosurface animation does not look like the movement of dye in time domain. Do you have any suggestion to make it more similar to the actual dye simulation?

Thanks again, Mike

James Date April 13, 2006 10:51

Re: dye simulation-followup
Run as a transient simulation with no re-start from initial conditions and plot out iso-surfaces at each time step.

mike April 13, 2006 11:44

Re: dye simulation-followup
Thanks alot James, Could you please make clear what you mean with no re-start from initial condition?, since I am using steady state solution as initial conditions.

Thanks again,


James Date April 13, 2006 12:02

Re: dye simulation-followup
I meant don't use a restart off a steady state solution. Let your simulation start from t=0s.

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