FLOWORKS - how to deal with mesh desity

Hello to all of you.

I'm simulating a (car)brake sequence in FloWorks, because i'm interested in the (disc)temp. vs time graph.

What i've done:
- modelled brake disc, hub and rim
- loaded the brake surfaces with 80kW "brake power"

Now, the results are HIGHLY dependent on mesh setting (see attachment.

Question:
should i deal with Floworks mesh as a ordinary FEA mesh, i.e. re-run with decreases elements untill results converge?

Any feedback highly appreciated, thanks!