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-   -   LES/DES in Star-CCM+ (https://www.cfd-online.com/Forums/star-ccm/68382-les-des-star-ccm.html)

 peresah September 17, 2009 08:03

LES/DES in Star-CCM+

Hi everyone :-)

I'm curious to know if anyone else has tried or can refer to published results on LES or DES applied in StarCCM+? Apart from the Star-CCM+ documentation, all I can find is CD-Adepco's press release.

Amongst other things, I'm interested/worried about StarCCM+ ability to conserve kinetic energy...

I'm modelling the viscous (possibly turbulent) flow near a pile subjected to ocean waves.

Kindly Peres

I made some DES but I miss a function to average the result to "filter" the eddys :(

 peresah September 21, 2009 13:12

Thanks for your reply! :-) I guess you refer to the fact that Star-CCM+ doesn't provide a scalar function for the area of each side of a cell (except boundary cells)? I don't know if it's a lame question, but what about using the scalar function "Volume" instead?

Did you achieve any further DES results (energy conservation of schemes, grid dependence etc.)?

1 Attachment(s)
Don't understand your first part :confused:

I did only one unsteady calculation.
Star CD shall have a average function...
I have attached you a picture where you can see what is possible.

 peresah September 22, 2009 02:28

Quote:
 Originally Posted by Maddin (Post 230046) Don't understand your first part :confused:
Thanks, I'll try to clarify. In your first post, you mentioned that you wanted a function to "average" (I guess, cell volume average?) the "results" (like velocity or kinetic energy?). So I suggested that this possibly could be done by using the "Volume" scalar function (e.g. as input into a user code).

Quote:
 Originally Posted by Maddin (Post 230046) I did only one unsteady calculation. Star CD shall have a average function... I have attached you a picture where you can see what is possible.
Can you state what scalar quantity your attached picture actually shows? ;-)

Thanks!

Hmm I think we write about the samebut I'm not sure.
I have no "included" function in CCM to average it over some iterations, I can't access to results from a step before.
With external tools I think it's possible, maybe TecPlot or something else.

The picture shows mole fraction :)

 peresah September 22, 2009 08:56

I think I understand now. You want to time-average the quantities. Yeah, that would require some external tools, macro or user code..

Thanks for stating what the picture was showing. Did you compare your results to other approaches (e.g. LES)?

Kindly Peres

I compared it with RANS but only to "show" that you can't compare it without time averaging...

 peresah September 22, 2009 12:03

Okay, that makes sense :-)

 peresah September 23, 2009 04:36

Did you also compare the averaged DES results with the RANS results?