title: Paraview. Volume fraction and/or mass flow rate
body: <p>My goal is to achieve something that was previously asked in <a href="http://www.cfdem.com/forums/volume-fraction-andor-mass-flow-rate" rel="nofollow noreferrer">this site (outside from SO)</a>. In this external site the questions is unanswered, and in order to give more visibility and to try to get an answer I translate it to here:</p>
  <p>The issue is:</p>
  <blockquote>
  <p>I have a small simulation of particles flowing through a wire mesh structure, and I'm interested in calculating the mass flow rate and volume fraction of particles at certain cross sections. I <em>think</em> I understand how to calculate mass flow rate by setting up small regions and dumping particle count and velocity from that region. I assume that volume fraction works in a similar fashion, except I only need to know the size of my particles and my dump region.</p>
  <p>What I'm wondering is this - is it possible to do these things in Paraview? I can set up planes and slices and such, but I can't seem to extract much useful information out of them.</p>
  <p>Further on down the road, what I would like to do would be to plot contours of volume fraction at certain planes, and plot the volume fraction along the vertical axis so I can see how high the particles are piling up on top of the screen, based on particle size, wire size, etc. Can Paraview do any of this?</p>
  </blockquote>
  <p>This is a visualization issue. I don't know how make it with Paraview. The idea is count how much particles cross the slice.</p>
  <p>My first approach was piped:  <code>DataReader | Spherical Glyph | Slice with normal fixed handly along z axis</code> but nothing results. Also I tried to adding the filter <code>Surface Flow</code> and nothing too. Probably I am piping the data in a bad way.</p>
  <p>To see the pipelining process I add an image (focus in PlotOverLine1 and its above pipes):</p>
  <p><a href="https://i.stack.imgur.com/5s7cW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5s7cW.png" alt="Image of ParaView" /></a></p>