[lgtmelo]

Good morning everyone. First of all, thanks in advance to whoever helps me.

I've been struggling with a model for a while now. To be objective, I'm trying to get the collision rate of 1micron diameter solid particles into a filter geometry on a simple tube. SST turbulence, turbulent dispersion force, fully coupled.

To do so, I have set the filter as a Wall with restitution coefficients of 0. From the inlet, 1000 particles run with zero slip velocity. When I run it as steady state, I get the number of captured particles on wall and that's it. However, my simulation never gave me a decent convergence (monitor wouldn't stabilize, residuals wouldn't go below 10^-3). So I studied a lot and improved it using many tips from this forum (thanks for that).

I gave up running as steady state and after running it as transient, adaptive, 3-5 coef. loops, I got the timestep of 1.5e-6; courant of 0 and max courant of 0.06; residuals below 10^-6; flat monitor graph. Ran again as transient using this timestep and everything is beautiful. (steady state reached, I believe?)

But when I run it as transient, I can't get the output I have been working with on steady state: "Entered domain: 1000; Captured on walls: xxxx; Left domain: xxxx". First of all, I only get 1 particle per iteration entering the domain. Secondly, if I understood correctly, for the 8s residence time I have in this model, for 1.5e-6 timestep, I'd need to run the transient model for 5 millions accumulated timesteps for it to end? Or should I just get the 1.5e-6 timestep and put it into the steady state model? Because when I do that, I dont get the same graphs - my residuals won't go as low, and my monitor won't stabilize.

I apologize if that's too big a post, but I tried to give all the info that would help understand my situation.

Best regards!