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July 12, 2012, 14:34 
how to polt surface elevation over time at a fixed point ?

#1 
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Teemo
Join Date: May 2012
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Hello,
I would like to plot a graph about wave pattern at a fixed point over time in paraview, but I dont know how to trace the free surface elevation, is there any way to do that without other 3rd party software? Regards, T 

July 12, 2012, 17:55 

#2  
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Bernhard Gschaider
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Quote:
If I understand you right with "fixed point" you mean coordinates ( x , y ) and you want to find the z so that ( x , y , z ) is on the water surface and then you want to plot z(t), right? This has been described on slide 135ff of http://www.openfoamworkshop.org/6th_...der_slides.pdf Disadvantage is of course that swak is ThirdPartySoftware. Advantage is that you can do this during the simulation and therefor get a finer temporal resolution than just taking the written times (but of course you can do that kind of calculation after the simulation with swak) 

July 13, 2012, 07:17 

#3 
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Teemo
Join Date: May 2012
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Hi,
Thanks for ur reply, sry for the bad description, I would like t plot the wave elevation z (t) at fixed (x, y) but I dont know how to trace the free surface. is there any way to achieve it in postprocessing, for example, any function in paraview since it take too much time to rerun the case 

July 13, 2012, 07:26 

#4  
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Bernhard Gschaider
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July 14, 2012, 14:13 

#5 
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Björn Windén
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Location: University of Southampton UK
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Hi.
I probe a number of points along a vertical line at (x,y) and then, using the values of alpha along that line, work out (using linear interpolation between the first point where alpha>0.5 and the last point where alpha<0.5) where alpha=0.5. I do this as a function object but I guess you could use probesDict and process it afterwards as well. //Björn 

July 20, 2012, 07:45 

#6 
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Teemo
Join Date: May 2012
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Hi Bjorn,
Thanks for you reply, could you send you a detailed work that how you achieve this (Teemo881123@gmail.com) ? I am new to OpenFOAM so I dont quite understand what is probesDict Many thanks, T 

July 20, 2012, 09:43 

#7 
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Hi,
I suppose you used interFoam? In that case, make a contour of places where alpha = 0.5. 

July 20, 2012, 09:52 

#8 
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Teemo
Join Date: May 2012
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hi Flowris,
I used waveFoam,based on interFoam, to simulate a wave tank. In paraview, I made a contour where alpha=0.5, but it only shows the free surface, how can I get the Y value (vertical) VS time at a fixed x and z point? Thanks, T 

July 20, 2012, 10:49 

#9 
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So first you make the contour plot, and then with the calculator, you color this surface using scalars > coordsY.


July 21, 2012, 08:05 

#10 
Senior Member

And to get the data from that contour you could either write a python script for the programmable filter in paraview or (this is a guess) you can have a look at the datapoints of the contour in a tabulated manner.


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