Tracking Free-Surfa...
 

Tracking Free-Surface of SPH Particles  

 

pjay
 pjay
(@pjay)
New Member
Joined: 2 months ago
Posts: 4
September 26, 2019 7:33 pm  

Hi All,

I am currently going through the LS-DYNA example of the dam-break wave generated by SPH particles ( https://www.dynaexamples.com/sph/intermediate-examples/wavestructure ) and I was wondering if there is a way to extract along a vertical line the free-surface elevation over time? Or conversely a 3D output of the free-surface of the SPH particles over time.

Thank you all for your time and consideration!


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Negative Volume
(@negativevolume)
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Joined: 10 months ago
Posts: 120
September 29, 2019 12:38 am  

Hi @pjay

So you are wanting to get the output of the maximum height of the wave for a specific plane over time? Is that correct? 


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pjay
 pjay
(@pjay)
New Member
Joined: 2 months ago
Posts: 4
September 29, 2019 3:02 pm  

Hi @negativevolume,

Yes that is correct, ideally I would like to take these measurements and compare them to experimental results from a flume to provide some sort-of calibration parameter. My initial thought is that you wouldn't be able to output a plane but rather a 3D shape as a SPH particle may never actually pass over that specific plane.

Cheers!

 


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Negative Volume
(@negativevolume)
Estimable Member Admin
Joined: 10 months ago
Posts: 120
November 7, 2019 12:10 pm  

@pjay

Did you ever find a solution to this? The only thing that I could think of would be going to Model -> Section and then creating a vertical section plane which you can drag to find the max height at a certain point in time. I believe you can also take some measurements using it. 


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pjay
 pjay
(@pjay)
New Member
Joined: 2 months ago
Posts: 4
November 9, 2019 3:15 pm  

@negativevolume

I never ended up finding a solution in LS-DYNA, I ended up creating a image processing script that used a video file output from LS-DYNA to extract the surface elevation, it is quite cumbersome though... Can't say I have ever tried using the vertical section plane, by drag do you mean basically setting the height of the section plane to be inline with the particles? I have also thought about trying to use tracers to export particle motion but what I have found is I would need a lot in order to get an accurate estimate.


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Negative Volume
(@negativevolume)
Estimable Member Admin
Joined: 10 months ago
Posts: 120
November 10, 2019 4:40 pm  

@pjay

Yeah so using the section plane function in Prepost to cut a number of sections and identify where the peak wave is and find what the height is. I've attached a picture below to show an example of this. You can even play the animation while keeping the cuts which may be useful to you. 

 

1573404036-section_cuts.png

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