code_saturne User's Forum

Hi to all!

I have some trouble in solving a natural circulation problem and maybe you can help me. I have a setup similar to that in the attached picture. The fluid is air and I have density defined as function of temperature. I do not know what the variable for inlet should be in order to obtain natural circulation. I tried with 0 velocity but what I obtain is far from natural circulation.

Any help will be nice.

Thanks,

Eduard

Hello,

Either inlet with velocity = 0 or a wall should be OK.

Did you define the gravity direction ?

Also, I am not sure natural convection works well with the "steady" flow option, so if this is what you are using, you may want to try to switch to converging an unsteady calculation.

Best regards,

Yvan

Yvan Fournier wrote:Hello,

Either inlet with velocity = 0 or a wall should be OK.

Did you define the gravity direction ?

Also, I am not sure natural convection works well with the "steady" flow option, so if this is what you are using, you may want to try to switch to converging an unsteady calculation.

Best regards,

Yvan

Thanks Yvan. I had defined g on OZ (not sure if the axis can be seen on the picture). With velocity zero at inlet I had already tried and not what I want. Today I tried your suggestion to define my inlet as wall and seems to work (more to be done) and I will also try unsteady calculation (I was using steady flow till now).

Eduard