October 17, 2022 at 12:14 amVickySubscriber
I am modeling a fluid of air and solid particles in a horizontal pipe, an unsteady fluid, DEM collision.
When I plot the DPM Velocity Magnitude, my results are consistent in the middle of the pipe but not near the wall. I've refined my mesh, and it stays about the same, meaning I don't get consistent results near the wall.
Could you explain why this is happening to me, or does it mean that the particles do not reach the wall?
October 17, 2022 at 8:40 amNikhil NaraleAnsys Employee
Hi, what do you mean by consistent? Are you comparing this with other similar simulations? If so, are you changing any settings?
'does it mean that the particles do not reach the wall?'
This depends on which forces are dominant. If the weight of the particles dominates over the pressure-gradient force of the continuous fluids, it should reach the wall (provided you have defined gravity correctly)
October 17, 2022 at 10:46 amRobAnsys Employee
To add, if the near wall mesh is very fine the particles get trapped in the viscous sublayer. Wall contact is only checked in the near wall cell, so we can finish up with "large" particles travelling parallel to the wall in the next-but-one-cell-layer that should have hit it. That's where Ansys Rocky may come into it's own.
October 19, 2022 at 11:18 pm
October 20, 2022 at 12:38 pmRobAnsys Employee
Can you plot DPM velocity contour and concentration; node values on & off? I wonder if there aren't any particles to get the data off.
October 20, 2022 at 5:57 pm
October 21, 2022 at 9:06 amRobAnsys Employee
In 2d don't select anything, that way you get the filled contour.
I think your problem is not the result but a lack of particles in cells towards the wall. As there's no particle there's no data to return so the curves look odd.
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