[OpenFOAM] Creating an average line in paraView

kayoneex · October 7, 2010, 09:01

Hello Users,

i have finished a simulation in OpenFoam which gets the wallShearStress over the surface. In paraFoam i can see all wallShearStresses over the whole object-surface.
Now my question: Can I lay a line over my model which gives the average of the wallShearStresses in paraView? How can i realise that in paraView? Is there a tool, for example that draws a line in x-direction over the model and gives the average of the wallShearStresses on this line?

Best regards,
Roland

kayoneex · October 17, 2010, 15:33

I have found it in the meantime.

chegdan · October 17, 2010, 17:30

Quote:

Originally Posted by kayoneex

I have found it in the meantime.

Could you share your procedure?

kayoneex · October 20, 2010, 08:18

Of course.

- Load your model in paraView.
- There is a tool called PlotOverLine. (Filters - Data Analysis)
- Now you can make a 2D-Line with the coordinatesyou need.
- Apply. paraView builds a graph (U or P etc..), where your sampled data is written in.
- Use the tool IntegrateVariables (Filters - Alphabetical) to get the average of this graph

Hopefully it can help.

Roland

subhkirti · October 22, 2010, 11:27

Hello kayoneex,

I am trying to get average velocity over a region and did as you suggested. However, I am not sure, that it is giving me the right values. The line is generated parallel to the x-axis at a certain y-coordinate. So, I suppose the velocity graph that I am getting is of the Ux velocity (most dominant in my case, one order of magnitude higher than Uy and Uz) in this region.

The graph that I have created using PlotOverLine gave me the following result, which is in the first graph. As you can see, the average velocity (Ux) will be in the region of 1.5. However, when I run the IntegrateVariables, I get the table, where the value of Ux is reported as 0.7932.

Am i missing something?

Quote:

Originally Posted by kayoneex

Of course.

- Load your model in paraView.
- There is a tool called PlotOverLine. (Filters - Data Analysis)
- Now you can make a 2D-Line with the coordinatesyou need.
- Apply. paraView builds a graph (U or P etc..), where your sampled data is written in.
- Use the tool IntegrateVariables (Filters - Alphabetical) to get the average of this graph

Hopefully it can help.

Roland

kayoneex · October 22, 2010, 11:59

Hello subhkirti,

yes that is my problem too. If you look at the field, that is generated when you use Integrate Variables, you get Ux, Uy and Uz. I tried to it with the formula squr(Ux²+Uy²+Uz²), but in my case the Uy is the dominant.
In my case it the average is in the same direction, but not exactly it. Maybe somebody can help with that problem...

kayoneex · October 25, 2010, 07:11

@subhkirti
I tried something... IntegrateVariables gives a magnitude about 0.13 for my wallShearStress. If i look at my graph it must be around 0.06-0.07.
I typed all magnitudes ( in my case 100), you get them from PlotOverline, in Excel. With AVERAGE(A1-A100) you get the average from wallShearStress or in your Case Ux. In my case ist is about 0.066. So its right.
Now my question:
Is there an oportunity to export all magnitudes from paraView in Excel????
Or can i get the average from my magnitudes somehow with the calculator in paraView????

Please help

kayoneex · October 25, 2010, 08:45

export: click on the plotOverLine-magnitudes.
then file, export save as .csv-file.
you can open this file with excel.

edit the .csv-file:
- data
- text in cleaving
- cutting comma
- replace comma with point , with .
- in an empty cell: average (...-...)

subhkirti · October 25, 2010, 10:30

Well, I am having a problem there. My export option is disabled when I am using the plotOverLine. How did you do it? I tried it exactly as you mentioned it, but something is missing i guess.

Quote:

Originally Posted by kayoneex

export: click on the plotOverLine-magnitudes.
then file, export save as .csv-file.
you can open this file with excel.

edit the .csv-file:
- data
- text in cleaving
- cutting comma
- replace comma with point , with .
- in an empty cell: average (...-...)

kayoneex · October 25, 2010, 12:38

Do you see your magnitudes in a list?
At the window of the PlotOverLine-graph in the upper right corner, there is a field called split horizontal. Click on it. Now you got a few options. Take the one which generates your magnitudes. It is one of the lower options.

Choose the whole magnitudes and click at Data - export ......

It must work...

kayoneex · October 26, 2010, 06:23

name of the option is: Spreadsheet View
and then in the showing-field: PlotOverLine
now you must see your magnitudes

mizzou · April 22, 2016, 22:50

Guys,

I just simulated a 2-D fluid flow inside a pipe. Now, I'd like to plot a graph showing the variation of the radial average of certain parameter (e.g. velocity, temperature, phase fraction, etc. ) along the pipe. How can I do that? I know that I can use plot over line to show the variation of a parameter along that line. But here, I am trying to depict the variation of average value of a parameter (average in each radial direction) along the whole pipe.

Thanks,

Nishant79 · April 23, 2018, 06:19

Quote:

Originally Posted by mizzou

Guys,

I just simulated a 2-D fluid flow inside a pipe. Now, I'd like to plot a graph showing the variation of the radial average of certain parameter (e.g. velocity, temperature, phase fraction, etc. ) along the pipe. How can I do that? I know that I can use plot over line to show the variation of a parameter along that line. But here, I am trying to depict the variation of average value of a parameter (average in each radial direction) along the whole pipe.

Thanks,

I have a similar problem. Did you find solution for plotting average value alonf the length?

dela · April 11, 2019, 02:09

Quote:

Originally Posted by Nishant79

I have a similar problem. Did you find solution for plotting average value alonf the length?

I am working on a similar problem too. any help would be greatly appreciated

HVonSch · September 21, 2020, 08:46

Apparently, the "Integrate Variables" Filter, if applied to "Plot Over Line", multiplies the average with the lenght of the line.

You'd have to divide that out in an additional "Calculator"-Filter.

The complete workflow originally posted by kayoneex would then be:

- Load your model in paraView.
- Apply PlotOverLine (Filters - Data Analysis).
- Now you can make a 2D-Line with the coordinates you need.
- Apply. Note down the line length.
- Use the tool IntegrateVariables (Filters - Alphabetical) to get the average of this graph
- Use the "Calculator"-Filter, choose "Point Data" and divide the relevant mean by the line length

Essentially this is the same as the tick "Divide Cell Data by Volume" in the "Integrate Variables" - Filter, which doesn't work here becaus we are handling "Point Data".

October 7, 2010, 09:01	Creating an average line in paraView	#1
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	Hello Users, i have finished a simulation in OpenFoam which gets the wallShearStress over the surface. In paraFoam i can see all wallShearStresses over the whole object-surface. Now my question: Can I lay a line over my model which gives the average of the wallShearStresses in paraView? How can i realise that in paraView? Is there a tool, for example that draws a line in x-direction over the model and gives the average of the wallShearStresses on this line? Best regards, Roland

October 20, 2010, 08:18		#4
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	Of course. - Load your model in paraView. - There is a tool called PlotOverLine. (Filters - Data Analysis) - Now you can make a 2D-Line with the coordinatesyou need. - Apply. paraView builds a graph (U or P etc..), where your sampled data is written in. - Use the tool IntegrateVariables (Filters - Alphabetical) to get the average of this graph Hopefully it can help. Roland yeyinglcn, Jomid and ateh like this.

October 25, 2010, 08:45		#8
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	export: click on the plotOverLine-magnitudes. then file, export save as .csv-file. you can open this file with excel. edit the .csv-file: - data - text in cleaving - cutting comma - replace comma with point , with . - in an empty cell: average (...-...) yeyinglcn likes this.

April 22, 2016, 22:50	Plotting	#12
mizzou Member Milad Join Date: Jul 2015 Location: USA Posts: 45 Rep Power: 11	Guys, I just simulated a 2-D fluid flow inside a pipe. Now, I'd like to plot a graph showing the variation of the radial average of certain parameter (e.g. velocity, temperature, phase fraction, etc. ) along the pipe. How can I do that? I know that I can use plot over line to show the variation of a parameter along that line. But here, I am trying to depict the variation of average value of a parameter (average in each radial direction) along the whole pipe. Thanks,

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October 17, 2010, 15:33		#2
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	I have found it in the meantime.

October 22, 2010, 11:59		#6
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	Hello subhkirti, yes that is my problem too. If you look at the field, that is generated when you use Integrate Variables, you get Ux, Uy and Uz. I tried to it with the formula squr(Ux²+Uy²+Uz²), but in my case the Uy is the dominant. In my case it the average is in the same direction, but not exactly it. Maybe somebody can help with that problem...

October 25, 2010, 07:11		#7
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	@subhkirti I tried something... IntegrateVariables gives a magnitude about 0.13 for my wallShearStress. If i look at my graph it must be around 0.06-0.07. I typed all magnitudes ( in my case 100), you get them from PlotOverline, in Excel. With AVERAGE(A1-A100) you get the average from wallShearStress or in your Case Ux. In my case ist is about 0.066. So its right. Now my question: Is there an oportunity to export all magnitudes from paraView in Excel???? Or can i get the average from my magnitudes somehow with the calculator in paraView???? Please help

October 25, 2010, 12:38		#10
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	Do you see your magnitudes in a list? At the window of the PlotOverLine-graph in the upper right corner, there is a field called split horizontal. Click on it. Now you got a few options. Take the one which generates your magnitudes. It is one of the lower options. Choose the whole magnitudes and click at Data - export ...... It must work...

October 26, 2010, 06:23		#11
kayoneex New Member Join Date: Oct 2010 Posts: 9 Rep Power: 16	name of the option is: Spreadsheet View and then in the showing-field: PlotOverLine now you must see your magnitudes

September 21, 2020, 08:46		#15
HVonSch New Member Hendrik von Schöning Join Date: May 2020 Posts: 7 Rep Power: 6	Apparently, the "Integrate Variables" Filter, if applied to "Plot Over Line", multiplies the average with the lenght of the line. You'd have to divide that out in an additional "Calculator"-Filter. The complete workflow originally posted by kayoneex would then be: - Load your model in paraView. - Apply PlotOverLine (Filters - Data Analysis). - Now you can make a 2D-Line with the coordinates you need. - Apply. Note down the line length. - Use the tool IntegrateVariables (Filters - Alphabetical) to get the average of this graph - Use the "Calculator"-Filter, choose "Point Data" and divide the relevant mean by the line length Essentially this is the same as the tick "Divide Cell Data by Volume" in the "Integrate Variables" - Filter, which doesn't work here becaus we are handling "Point Data".