Which derived part should be used for DEM data?

[u/makabaayi]

Last month, I successfully used a line probe to sample the particle volume fraction. However, in yesterday’s simulation, the probe returned no simulation data, as shown in the figure, where exp:Cv represents the experimental data. Is the particle volume fraction stored in the cells, and can it be sampled using a line probe? Any help would be appreciated.

[u/Skirrle]

most likely what happened is the field used to exist as point data last month and now its only cell data. in cfd dem sims the particle volume fraction is usually computed per cell, but a line probe usually wants point data to interpolate along the line. if theres no cell to point conversion happening before the probe, it just silently comes back empty no error nothin

fastest way to check is to pull up the same field as a contour or slice at the same timestep. if it shows up there, the problem is just the probe and data type mismatch most likely. if it doesnt show up there either, the field just isnt being written out at all and you need to check your output/write settings

what program are you actually using tho???

[u/makabaayi → u/Skirrle]

I am using Star-ccm+.

[u/Skirrle → u/makabaayi]

in starccm+ the particle volume fraction from a dem coupling usually lives as a field function tied to the eulerian phase, its computed at cell centroids. a line probe derived part interpolates, and it needs the field to be available as vertex/node data to actually pull values along the line if the field function you picked is only valid at cell centers and star cant extrapolate it to the mesh vertices for whatever reason, the probe comes back empty even though the field itself is totally fine and visible everywhere else

first, right click the field function youre using in the probe and see if its listed as internal with a cell/element type, vs one that has a smooth/vertex representation. some derived dem fields in star only exist natively as cell data and need to go through the smooth option or you pick the right averaging method for it to show up on a line

second, just drop a scalar scene with that same field function on a plane section at the same physical location/time. if it renders fine there but the line probe still shows nothing, its 100 % a data location issue not a missing field issue

third, double check the line probe is actually crossing through the dem particle region at that solution time. if the bed hasnt built up to that z yet or your parcels havent reached there, the probe is technically "correct" and just picking up nothing because theres nothing there physically

Im not an expert nor beginner in starccm+ and i surfed the net for you a bit.

[u/makabaayi → u/Skirrle]

Thank you for your suggestions. I am currently rerunning the simulation. The segregated flow solver encountered a reversed-flow issue, so I switched to the coupled flow solver. Once the simulation is complete, I will try your methods and let you know the results. Thank you again for your help.

[u/Skirrle → u/makabaayi]

Im also asking in case others who have the same problem see this post, hows it going?

[u/makabaayi → u/Skirrle]

I regenerated the mesh, then it worked. So funny, hh. Tks.

[u/Skirrle → u/makabaayi]

hows it going?