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-   -   high deviation between CFX and experiment (https://www.cfd-online.com/Forums/cfx/173417-high-deviation-between-cfx-experiment.html)

yaseen wsu June 19, 2016 11:07

high deviation between CFX and experiment
 
2 Attachment(s)
hello
I simulated free surface flow but the result show a very large difference between CFX and experiment, as well I take measurements at VF 0.1 at the location shown in attached image (has high air concentration) so:
1- CFX can predict flow in such condition?
2- I used supercritical outlet boundary condition according to ANSYS CFX guide and homogeneous multiphase flow
please help me in this problem.

http://www.cfd-online.com/Forums/att...1&d=1466348828
http://www.cfd-online.com/Forums/att...1&d=1466348829

ghorrocks June 19, 2016 20:16

FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

yaseen wsu June 20, 2016 03:04

Quote:

Originally Posted by ghorrocks (Post 605633)

OK, I read this FAQ, this problem not related to (mesh size, BC ...) because I did sensitivity analysis for mesh size. and this error occur in the location of high entrainment, in fluent three multiphase available (VOF, Mixture, Elurian) but in CFX (Elurian (homogeneous and non homogeneous), particle tracking) is that good classification? some peple said VOF+LES is best to handle flow simulation in high entrainment area, but I don't know in CFX, I test (sst, rngk-e, k-e)model
according to above classification (homogeneous is not equivalent to VOF in fluent) can you discuss ???, because I have problem only in this location

ghorrocks June 20, 2016 07:40

You seem to be asking four questions in one sentence. Can you explain your question more clearly?

CFX supports all the options you discuss, so why not give them a go and see which works best?

zryan civil June 20, 2016 15:27

Quote:

Originally Posted by ghorrocks (Post 605698)
You seem to be asking four questions in one sentence. Can you explain your question more clearly?

CFX supports all the options you discuss, so why not give them a go and see which works best?

I have the same problem, I used homogeneous multiphase (Elurian) with (k-e) but there results are in correct at high entrainment location, but I don't know this method is equivalent to VOF ?,


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