[svaezi]

Hi every body
I have a question about natural convectin in cfx
We have a collector that air changed density in it and arise up
Now we wnat to know we shoud use boussonesq with air 25c or ideal gas???
If we set bouyant model for air 25c boudsinesq approximation set automatically???

[evcelica]

Does the temperature change much? If not, use Boussinesq. if so, you will have to do the full buoyancy model, and use ideal gas law for density instead of constant density with the expansion coefficient. If you have constant density, then yes it will be boussinesq since that is the only way it could work. Use variable density for full buoyancy model to work.

[svaezi]

thanks a lot evcelica