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-   -   Trouble with Sample output file (http://www.cfd-online.com/Forums/openfoam-post-processing/63535-trouble-sample-output-file.html)

lth April 11, 2009 19:59

Trouble with Sample output file
 
I am using the solidDisplacement tutorial, but when I run sample, it runs, but there is no Sample output file. Are there problems with the sample utility. Anyone know how to resolve this:confused:. In the end, I'm trying to export raw data from paraFoam.

Thank you, Lori Holmes

maja April 23, 2009 09:33

Hi, I need to calculate massflow average of total pressure on the outlet and on the inlet. I am trying to use sample utility to get phi on these two patches. I put a sampleDict into the system directory. When I run sample, there are no errors reported and it works fine with U and p, but I do not get phi. I do not get mag(U) or any Ucomponents either. What shoul I do?
Thanks for help!

santos April 23, 2009 10:06

Hi Maja,

As far as I know, the sample utility does not work for patches.

Please try the following:
patchAverage phi inlet && patchAverage phi outlet

Regards,
Jose Santos

maja April 23, 2009 10:46

Thanks Jose for your quick reply!
On one of the previous discussions (http://www.cfd-online.com/Forums/ope...ampledict.html) I found:
surfaces
(
leftWall
{
type patch;
patchName leftWall;
interpolate true;
triangulate true;
}
);

I wrote a similar thing:
surfaces
(
outlet
{
type patch;
patchName outlet;
interpolate true;
triangulate false;
}
);

fields
(
U.component(2)
phi
mag(U)
U
p
);

I only get U and p.
Unfortunately I need patchAverage (phi*ptot)
Any better idea?

Thanks a lot for your help, Maja

Subodh June 1, 2009 22:50

Hi Maja,

You are right, I had not tested it before. I just tried to sample for phi, and it does not work. I tried with p, U and phi. As you stated it only work for p and U. I also need phi because i want to calculate mass average. Do you come across any solution or workaround.

Thanks
Subodh

maja June 2, 2009 02:00

Hi Subodh,
Unfortunately I have not find a solution to this problem yet. I only realized that sample works only with vector fields, which phi is not. If you look at the phi file that you get at each timestep after solving the case, you can see it is calculated on face centers and not on cell centers like velocity, for example. From these files I also found out it is not calculated on the patches, which is probably the reason why sample does not work for patches, as Jose said.
But anyway I need to calculate a mass average of total pressure on the inlet and on the outlet which I need for calculating the efficiency of a water turbine. So, I am still working on it. If you find out anything, I would be very glad to hear.

Regards, Maja



Quote:

Originally Posted by Subodh (Post 217860)
Hi Maja,

You are right, I had not tested it before. I just tried to sample for phi, and it does not work. I tried with p, U and phi. As you stated it only work for p and U. I also need phi because i want to calculate mass average. Do you come across any solution or workaround.

Thanks
Subodh



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