Big Artifacts in Simulation

[Anonymous]

Hi, I've tried to search for a existing topic but no luck... Sometimes when i'm simulating in CFD some weird artifacts start showing, and they interfere with my results, someone have a fix for this? All my drivers are up to date... I'm using CFD 2017

[Jon.Wilde]

Is this due to the rotating region? How do you know it is effecting your results?

Is this simply a single cut plane?

[Anonymous]

This is the model:

This is the Rotating Region

The setup is a inlet Fluid Air - Piecewise Linear flow accelerating from 0km/h (T=0s) to 30km/h (T=30s) and then a steady flow of 30km/h (T<30s), outlet pressure 0, sides/bottom= slip/symmetry, adv5, hydrostatic pressure on, SSTomega... The RR is a freespinning flow driven with 2.6kg/m² constant inercia, angular motion z axis with 2.0n/m resistive torque, Mesh outbox 200 (mm), RR region 35 (mm)...

What you see in the first images are a plane cut XY shaded mesh...

I've done similar models, actually the same model with just the impellers on a different angle... About 10 of those, and they all appeared some red lines but they never glitch like this... Well, every time that the artifact show in the screen there is a spike in air flow speed... This is normal?

[matt.bemis]

Hi @Anonymous,

This does not ring a bell. Do you think it's graphics related or is it affecting the results? I would definitely disable hydrostatic pressure- I sort of doubt it is important here. A combination of of rotating region, transient BC's, and motion is pretty complicated. If the issue keeps persisting I would probably start disabling some of the physical details in the simulation. Maybe start with a rotating region, steady state BC's, no hydrostatic pressure and no motion. Keep adding details and see if when the error is introduced.

Hopefully this helps a bit!