Wonky particle paths

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mgoddard
Posts: 13
Joined: Wed Dec 23, 2015 11:00 pm
Location: Canada
Location: Netherlands

Wonky particle paths

Post by mgoddard » Tue May 16, 2017 9:01 am

Why do some particles have such a wonky paths after they leave my section? This only seems to happen when water leaves the upper most seepage boundary. How can I fix this?

Thanks,
Marie
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wonky particles.jpg
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Jirka
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Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Wonky particle paths

Post by Jirka » Tue May 16, 2017 10:08 pm

I do not think that we can answer this without seeing the project itself and, for example, understanding what your BCs are. J.

mgoddard
Posts: 13
Joined: Wed Dec 23, 2015 11:00 pm
Location: Canada
Location: Netherlands

Re: Wonky particle paths

Post by mgoddard » Wed May 17, 2017 7:05 am

Along the upper boundary I have flux and seepage boundaries. In the attached screenshot the flux is constant (steady state) but I also have the same model set up for variable flux. The basal unit is no flux. The western vertical boundary is free drainage.
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wonky particles3.jpg
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wonky particles2.jpg
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Mirek
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Re: Wonky particle paths

Post by Mirek » Fri May 19, 2017 7:09 am

Hi Marie,
if you send us your project, I can look at it in the debugger. Otherwise I do not have any explanation - I have never seen a similar problem. Please ZIP your project or copy it to a FTP server if the ZIP size is too large (>10 MB).
Mirek

Jirka
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Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Wonky particle paths

Post by Jirka » Sun May 21, 2017 5:55 am

You print the particle trajectories only at print times. Had you printed the particle trajectories at each time step, you would have seen that the particles travel all the way to the upper boundary and cross it (x_new=x_old+velocity/theta*dt). Once a particle crosses the boundary, the algorithm is suppose to place it back at the boundary. For some reason (I have not studied that in detail), for particles 14 and 16, it places them at zero z coordinate. J.

mgoddard
Posts: 13
Joined: Wed Dec 23, 2015 11:00 pm
Location: Canada
Location: Netherlands

Re: Wonky particle paths

Post by mgoddard » Sun May 21, 2017 7:55 am

Thank you for the answer and the information about print times.

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