Hi Tony, hi Darren,
I set up a quick simulation with coarse automatic mesh and reduced boundary box to speed things up for some experimenting.
The first was just a simple reference run with the default parameters.
By the second I changed the solver types to Smooth solver.
Unfortunately I typed 20m/s instead of 50 at the runs so I’m running a third one with Smooth solver as well.
First run force plot (run time: 15"):
Second run force plot (run time: 34"):
In both cases the drag force is around 131N which gives a drag coeff of about cD=0.54.
My conclusion is that using Smooth solver doesn’t really improve result quality neither convergence although the initial phase is much smoother. The big hump near the end in both cases is quite strange for me. Do you have any idea what happened there?
I’m wondering about what Darren said. How do you define the magnitude of relaxation factor? Is it something that can be calculated, or some kind of experience?