Hi Folks! Sharing this on the SFX forum in the hopes that some more ideas might surface…

I'm wondering if anyone has run into this and found a good solution, it's been popping up in my low-to-mid viscosity sims for a while. Perhaps I'm missing something stupidly obvious? Collision geo/field are fine and the interface between fluid and collision object looks great before turning on viscosity, then I get these grid artifacts that are tough to get rid of. Reducing Surface Extrapolation way down in Volume Collisions helps but doesn't completely remove the artifacts. Also, using a high slip-on-collision value helps, but I usually don't want the sliding behavior with sticky viscous fluids. Reducing Grid Scale reduces the relative grid size and helps too, but the artifacts are still there, just smaller.

Attached file is somewhat of a worst-cast example, just curious if other folks have dealt with this before. I know I can run some post-sim tweaks to clean up the collision surface intersection, but I've also noticed that the artifacts reveal themselves on the outer surface of the fluid if it gets thin enough, which is not so easy to fix…

01 - viscosity disabled

02 - viscosity enabled

03 - viscosity enabled, surface extrapolation 0.01

Thanks in advance for any help/ideas!!

–Dave