difference of velocity field processed by CFD-POST and Fluent

Jiuan · June 15, 2010, 04:28

Dear All,

I used both CFD-POST and Fluent post-processing tool to show the velocity vector in a certain surface. The velocity magnitude by these two tools are different. Why? And how to fix the difference? How can get the same result by CFD-POST as the one by Fluent post-processing tool? Thanks.

ghorrocks · June 15, 2010, 07:51

CFX and Fluent use different control volumes and therefore Fluent is probably doing some interpolation onto different control volumes when it displays CFX data. Either that or CFX does not correctly show the hybrid/conservative variable issue correctly. Either way CFD-Post is the correct one and has been designed to correctly show CFX results.

Jiuan · June 16, 2010, 02:52

Thanks.

I get the simulation result by Fluent. In this case, is Fluent itself post-processing tool is better to show the result?

ghorrocks · June 16, 2010, 09:23

If the simulation was done in Fluent then CFD-Post has to do some interpolations onto CFX control volumes. In this case the Fluent post-processor is the one to benchmark off. But the differences should be very small.

June 15, 2010, 04:28	difference of velocity field processed by CFD-POST and Fluent	#1
Jiuan Member Dongzi Wei Join Date: Mar 2009 Posts: 33 Rep Power: 17	Dear All, I used both CFD-POST and Fluent post-processing tool to show the velocity vector in a certain surface. The velocity magnitude by these two tools are different. Why? And how to fix the difference? How can get the same result by CFD-POST as the one by Fluent post-processing tool? Thanks.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FLUENT bug in cartesian-cylind velocity conversion	Knut	FLUENT	0	September 3, 2008 11:52
Axial, Radial, Tangental velocity in FLUENT post	Barri	FLUENT	2	March 6, 2008 21:29
Fluent -post	Dan	FLUENT	1	February 14, 2007 11:29
fluent for post processing	James	FLUENT	0	April 21, 2006 05:43
PC vs. Workstation	Tim Franke	Main CFD Forum	5	September 29, 1999 16:01

June 15, 2010, 07:51		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	CFX and Fluent use different control volumes and therefore Fluent is probably doing some interpolation onto different control volumes when it displays CFX data. Either that or CFX does not correctly show the hybrid/conservative variable issue correctly. Either way CFD-Post is the correct one and has been designed to correctly show CFX results.

June 16, 2010, 02:52		#3
Jiuan Member Dongzi Wei Join Date: Mar 2009 Posts: 33 Rep Power: 17	Thanks. I get the simulation result by Fluent. In this case, is Fluent itself post-processing tool is better to show the result?

June 16, 2010, 09:23		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,850 Rep Power: 144	If the simulation was done in Fluent then CFD-Post has to do some interpolations onto CFX control volumes. In this case the Fluent post-processor is the one to benchmark off. But the differences should be very small.