Define monitorine point for Pressure

hhm747 · November 25, 2015, 21:03

Hello everybody,

I performed an unsteady simulation of turbine during a transient process in order to evaluate the pressure in some monitoring points on the runner.
I defined the monitoring points and they worked.
After convergence, I found that I need to monitor the pressure fluctuation in other places.

Do you know how I can obtain the pressure fluctuations from the result file at new points?
Do I need to lunch it again?

Thanks

tomson199 · November 26, 2015, 03:28

You think about CFD Post? If yes, use a point and place it anwywhere where you want in the space. Then you can plot pressure in this point vs time in chart option in CFD-Post

It is very simple action.

hhm747 · November 26, 2015, 09:13

Hi Thomas,

Thank you for your kind comment.

I agree with you for using chart and it works.
But the chart only shows the pressure at last time.
I need the variation of pressure at different time steps not at specific time. Attached files show the data series of pressure at a point. It shows the pressure value at t=3.06153011e+000 sec.

Regrads
HHM

pree2.jpg

press.PNG

-Maxim- · November 26, 2015, 09:38

set a monitor point in CFX-Pre. You can display your monitor points in the solver manager and save all data points for each time step directly from the solver manager (right click on plot monitor).

in case your simulation is done and you need more monitor points, you can load your backup files of your transient simulation (assuming you saved every XX time step) and get the data from those backup files. You can select different time steps in the timestep selector.
If you haven't set your simulation in a way that it saves every xx time step as a full result, I think you have to run your simulation again

tomson199 · November 26, 2015, 09:47

Everythig important Maxim said before me

hhm747 · November 26, 2015, 10:10

Hi Maxim,

Thank you for commnet.

At unsteady simulations, I calculated the pressure variation from the solver manager at defined monitoring points like you.
In this case, I needed to compute a new point that was not defined at pre-proceesing.
It seems that I can not display pressure variation during transient process at post-procssing. Thus I need to lunch it again with new monitoring points.

-Maxim- · November 26, 2015, 10:19

yeah, in case you want to be able to do that, you would have to save all variables for each time step. That means a complete result file would be written for every time step. In theory, this is possible but not recommended of course. You can imagine that your computer would be quite busy writing a 5-10GB file for every iteration.
For my current project, I save every 25th time step for example.

November 25, 2015, 21:03	Define monitorine point for Pressure	#1
hhm747 New Member Hossein Join Date: May 2015 Posts: 11 Rep Power: 11	Hello everybody, I performed an unsteady simulation of turbine during a transient process in order to evaluate the pressure in some monitoring points on the runner. I defined the monitoring points and they worked. After convergence, I found that I need to monitor the pressure fluctuation in other places. Do you know how I can obtain the pressure fluctuations from the result file at new points? Do I need to lunch it again? Thanks

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November 26, 2015, 03:28		#2
tomson199 Member Thomas Join Date: Dec 2014 Location: Poland Posts: 49 Rep Power: 11	You think about CFD Post? If yes, use a point and place it anwywhere where you want in the space. Then you can plot pressure in this point vs time in chart option in CFD-Post It is very simple action.

November 26, 2015, 09:13		#3
hhm747 New Member Hossein Join Date: May 2015 Posts: 11 Rep Power: 11	Hi Thomas, Thank you for your kind comment. I agree with you for using chart and it works. But the chart only shows the pressure at last time. I need the variation of pressure at different time steps not at specific time. Attached files show the data series of pressure at a point. It shows the pressure value at t=3.06153011e+000 sec. Regrads HHM pree2.jpg press.PNG

November 26, 2015, 09:38		#4
-Maxim- Senior Member Maxim Join Date: Aug 2015 Location: Germany Posts: 415 Rep Power: 13	set a monitor point in CFX-Pre. You can display your monitor points in the solver manager and save all data points for each time step directly from the solver manager (right click on plot monitor). in case your simulation is done and you need more monitor points, you can load your backup files of your transient simulation (assuming you saved every XX time step) and get the data from those backup files. You can select different time steps in the timestep selector. If you haven't set your simulation in a way that it saves every xx time step as a full result, I think you have to run your simulation again

November 26, 2015, 09:47		#5
tomson199 Member Thomas Join Date: Dec 2014 Location: Poland Posts: 49 Rep Power: 11	Everythig important Maxim said before me

November 26, 2015, 10:10		#6
hhm747 New Member Hossein Join Date: May 2015 Posts: 11 Rep Power: 11	Hi Maxim, Thank you for commnet. At unsteady simulations, I calculated the pressure variation from the solver manager at defined monitoring points like you. In this case, I needed to compute a new point that was not defined at pre-proceesing. It seems that I can not display pressure variation during transient process at post-procssing. Thus I need to lunch it again with new monitoring points.

November 26, 2015, 10:19		#7
-Maxim- Senior Member Maxim Join Date: Aug 2015 Location: Germany Posts: 415 Rep Power: 13	yeah, in case you want to be able to do that, you would have to save all variables for each time step. That means a complete result file would be written for every time step. In theory, this is possible but not recommended of course. You can imagine that your computer would be quite busy writing a 5-10GB file for every iteration. For my current project, I save every 25th time step for example.