Hi !

I need to post-process a simulation with a free surface, so as to count the particles belonging to this free surface. By free surface particle, I mean a particle with no neighbors on one side : a particle in contact with a boundary should not be counted.

Any idea ?

My final target is to calculate the sum over time of all the free surface particles.

• edited October 2018
Just throwing it out there but a simple solution might making a piece of code which sorts particles based x a very small x interval:

And then the free surface would be the particles with the heighest z position.

Please note that this this solution is not useful for more complex cases, but this might be a quick and dirty solution, as long as it is possible to make the x interval sufficiently small.

Edit: Actually this might no be effective if you have some sceneria to like the right of the included picture - the free surface would there be on both sides. Keeping the comment up if it might be helpful for anyone anyways.
• Thanks for the answer Asalih3d.

For the time being, since I cannot modify the code itself, I'm working on the *.vtk files.

I'm using two files : the "bounds" file, and the "isosurface" file, checking all the distances between pairs of points. If, for a specific point belonging to the isosurface file, the distance to all the points of the "bounds" file is more than a specific threshold, I considere the point as belonging to a free surface. Quite a long and clumsy processing... !
• Ah okay that is also a viable way of doing it - if you want I guess you could use the threshhold of your computational domain instead to simplify more complex cases a bit, but you will know better if that works or not for you.

Ideally it would of course be nice if there was a way to see which particles were considered "Free Surface" during simulation, but as far as I know there is not. Maybe someone else will chime in with a piece of gold soon :-)
• MeasureTool allows you to compute the surface elevation (-height) along the simualtion at fixed positions.

Regards