Energy equation convergence acusolve (thermal analysis - natural convection)
Hi all,
I am having a tough time trying to reach convergence regarding temperature residuals in a 3D natural convection problem. It consists of a box cointaining an hole in the middle which releases heat flux per unit area into the fluid.
The BCs are:
Fixed temp on the outer wall.
Heat flux on the walls of the square hole.
The solver settings are:
Boussinesq density model
laminar flow
relaxation factor 0.2
My questions are:
1. Are there separate relaxation factors for each one of the residuals (velocity, pressure, temperature) ? I only see 1 global relaxation factor.
2. How can I check the regions with bad convergence? In this post,
https://community.altair.com/community?id=community_question&sys_id=88b600ba1b2bd0908017dc61ec4bcbf1
ydigit explains that there is an option of outputting advanced varaiables. ¿How can I do that and how do I visualize the "bad" regions?
3. Any recommendation on large models? I can get convergence in a small model of size 0.1 m x 0.1 m, where residuals of temperature are <1e-3. However, I have a model of 1.5 m x 1 m size, I can not afford putting the same element size I used in the small model and the temperature residuals I am getting are around 0.1 after testing various mesh densities. On the other hand, Is it possible or is it a usual practice to do similarity analysis?
Thank you