Discussion Forum

First, two caveats: (1) I can't actually run your model because I don't have at least some of the necessary license(s), and (2) I seldom do fluid models, so please don't trust my advice too much! That said, I took a look at your file anyway. Hmm! Now, again, I am probably just not sufficiently familiar with this type of model, but I just have to ask: where did you specify (or try to specify) a non-zero fluid velocity? Every place that I looked, where it seemed (to me) possible to specify a fluid velocity, it also seemed that the fluid velocity was being defined to be zero! But I probably just missed it (really, no kidding), so... where should I (or anyone else, who may wish to help you) look for it? You specified that velocity somewhere, right?

The fluid velocity is specified as the "outlet" B.C. of the laminar flow module - the actually velocity field (spf.U) is specified in the TDS2 module, but the two physics are coupled. I just plugged in an abritrary value for the fluid velocity to verify that it would give the same results (for example the actual outlet velocity is related to the diffusion rate as calculated in the stationary step, but this is not the issue)

Ah, now I see it! Thank you. But of course I don't know enough about this kind of problem to actually help you. Sorry about that. So the same approach worked in axi-sym 2D, hmm? I'll bet you must have done something different there, but otherwise I have no idea. Maybe you should post that model too? Perhaps someone else here can figure it out. Best wishes and good luck!

p.s. You've got a rather complicated set of couplings and physics going on here. Are they set up in exactly the same arrangement/order as in your successful 2D models? Might there be a subtle difference that is to blame in the 3D case? If you haven't already, I suggest you compare the 2D vs 3D models closely, including all the bcs, solver configurations, etc. It might take some time.

Thank you for your input. I think the issue was that all time dependent solutions/dependent variables were being stored in the solution store I defined for the stationary solver. In my 2D model, I had separate solution stores / dependent variables for the stationary and time dependent variables. Now I am getting the error "Failed to find consistent initial values." Just replacing one problem with another, I guess.

I've tried a few fixes but haven't had any luck, so I'll keep troubleshooting.

Sounds good. Methodical perseverance is often necessary! When you succeed, just be sure to tell all your coworkers that it was easy.