Boundary condition for natural convection
 

Assalam o Alaikum

Sir i have a gemoetry i.e annuli. The inner wall of annuli is given a constant heat flux and the outer wall is adibatic. but i don't know what type of boundary condition i have to specify on the the top and bottom walls of this geometry.

i want to find that with which velocity the atmosphere air will enter in the annuli space and at which velocity it will leaves the annuli and whats the possible convection coeffecient...

The annuli is placed in open atmosphere .. the air can enter in it from the bottom..

Hi, I think your problem is very similar to this thread:
http://www.cfd-online.com/Forums/sho...d.php?t=150239

Reply
 

i tried to read the paper that you attached but i failed to implement this in fluent because my numerics are not strong.. :o

What do you mean by domain extent method..?

I mean to include your actual domain in a bigger domain, and move boundary conditions away from your actual domain so to limit the interference of boundary conditions in respect to your annular zone.