tri3_buoyancy fails about lgrtk

[ibaned]

Does this still happen? I think it was due to the F update bug I fixed.

[bgranzow]

Yes. It was after that bug fix that I saw it. It will also just happen all the time if you just increase the final time slightly (say to 2.1) on any machine. The upper bubble just starts flying of to the left.

[ibaned]

Its still TBD whether this is a bug in remap or something more fundamental about timesteps...

[ibaned]

In particular, I think I tried a remap that just picks old F values and that still showed the same behavior

[ibaned]

Thankfully, it looks like this is an issue with linear elastic, if I switch to neo-Hookean things get better. Of course this is with many code edits...

[ibaned]

Let me know if my most recent push to use neo-Hookean fixed it, it ran fine for me with the original code

[bgranzow]

Yea that seems to work. Can this be explained by the fact that linear elastic isn't valid for large rotations?

[ibaned]

Yea large deformations would be one thing to think about... I'd say we simply steer clear of linear elastic for anything that is adapting