how to polt surface elevation over time at a fixed point ?
 

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

Define 3rd party software? And does it have to be paraview?

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 ThirdParty-Software. 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)

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 post-processing, for example, any function in paraview since it take too much time to re-run the case

Paraview I don't know, sorry (maybe by writing your own filter in Python with ProgrammableFilter). With funkyDoCalc you could do it in swak though

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

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

Hi,

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

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

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

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.

Hi GSchauder
I'm interested in that method using swak. But slides are not available anymore. Any chance to get them from somewhere else?

The presentation can be found here https://openfoamwiki.net/index.php/C...er_information (right on top of section 7.2 - The one from the 6th Workshop). There are also example files but I assume they won't work on modern OpenFOAM-versions

OK thank you.


On the same website 7.2.2 has a tutorial on the topic.