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-   -   Collect transient results CFD POST (http://www.cfd-online.com/Forums/cfx/109356-collect-transient-results-cfd-post.html)

mortain November 15, 2012 11:33

Collect transient results CFD POST
 
Hello,

I am relatively new to the forum and to CFD world.
I am designing a turbulence grid and I wanted to check that the place where the probe will be inserted is enough downstream compared to the grid in order to have an homogeneous flow at the probe.

I have simulated the grid, in a transient simulation with k-e model.

Why transient, well, I wanted to see the turbulence level which CFD was going to give to me.

I have the simulations and using CFD post I wanted to evaluate the velocity in a point of the domain, in order to calculate the velocity fluctuations.

I was trying to code with CEL language:

1) create the point
2) evaluate the velocity in Point 1
3) save the value in a table
4) save the table

but I don't know how to open all the transient results in order to get the velocity, does anyone have a suggestion, please? Do you think there's an easier manner?

Cheers,
Antonio

cdegroot November 15, 2012 12:52

Probably the easiest thing to do is load the full run history. When you open the res file, select the last one and make sure "Load complete history" is selected.

mortain November 15, 2012 13:21

Quote:

Originally Posted by cdegroot (Post 392322)
Probably the easiest thing to do is load the full run history. When you open the res file, select the last one and make sure "Load complete history" is selected.

if I do as you say, then how can I output the velocity history?

cdegroot November 15, 2012 13:24

You can make a time series chart and export the results as a csv file.

mortain November 15, 2012 14:10

Quote:

Originally Posted by cdegroot (Post 392332)
You can make a time series chart and export the results as a csv file.

Cool, did not know there was chart for time history. It works perfectly. Thanks a lot for your help!
It takes a bit of time to open all the different files....but it;s better than coding!

cdegroot November 15, 2012 14:22

Great, glad to help. You are right, it does take a while to load, but it's a pretty easy solution once it does.

monkey1 November 19, 2012 07:49

Another (faster) way to get a time dependent variable value at fixed points:
Create a monitor (or several monitors) point in CFX Pre at the the location of your point1 and with in your case the velocity to be monitored.
In the CFX Solver you can now see the Monitor point plotted over the simulation time. There you are also able with a right click on the graph to export it as csv.
That way you just avoid opening all trn files in Post.

A second way is to use a perl/CEL Script wich writes you a csv file with all the information required.
If this is of interest for you just have a look at this thread. I posted an exampe file there.
http://www.cfd-online.com/Forums/cfx...tml#post385850


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