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-   -   monitoring variables in a transient simulation (http://www.cfd-online.com/Forums/cfx/20603-monitoring-variables-transient-simulation.html)

Craig Johansen August 27, 2004 22:57

monitoring variables in a transient simulation
 
I am modelling the decay of isotropic homogeneous turbulence in a cubic domain with boundary conditions using LES. I would like to save the velocity correlations (all of them uu, uv, uw, vv, vw, ww) at a single node at the center of the domain at EVERY TIME STEP. I need to export these values as a text file.

I want a text file with 7 columns of data at point (0, 0, 0), which is the center of my domain:

Column 1: time Column 2: uu Column 3: uv Column 4: uw Column 5: vv Column 6: vw Column 7: ww

Can CFX do this?

Thanks,

Craig

Glenn Horrocks August 29, 2004 19:36

Re: monitoring variables in a transient simulation
 
Hi,

Yes, CFX can do that.

Glenn

Craig Johansen August 30, 2004 13:05

Re: monitoring variables in a transient simulation
 
This is done through the Monitor output controls, right?

What if I want to save a plane of data at different times? In the monitor options, I can only select a single point.

How do you save a plane of data at different times?

I do not want to use transient results because then I have to manually go to each transient file and save each plane of data.

Thanks

Glenn Horrocks August 30, 2004 18:00

Re: monitoring variables in a transient simulation
 
Hi Craig,

1) The easiest way to output data from a single point is using monitor points. You can extract data from these points as the simulation progresses (or is finished) using the solver manager.

2) For a plane of data, you can either generate a number of monitor points;

2a) or if you want an average over the plane you have two choices: 1) generate transient results files and generate the plane data in CFX-Post (this is the best option generally), or 2) place an interface or subdomain in the region of interest and use a monitor point with an average average/volume average function. This involves generating a new mesh.

3) You cannot save a plane of data at different times in the solution.

4) You do not have to manually go through each transient result file to get the plane data. You can write a CFX-Post script and it will zip through them all.

Glenn

Sigve September 4, 2004 06:58

Re: monitoring variables in a transient simulation
 
Note that exporting monitor points to a text file also includes innerloop values for each time step.

This is useless information and should be removed from CFX 5.7.

Aline Luz Salgado October 6, 2004 08:10

Re: monitoring variables in a transient simulation
 
Hi Glenn,

Could you explain me how can I write a CFX-Post script?


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