boussinesq approx
 

in the fluent user's manual it says for natural convection flows, the boussinesq approximation is valid when

Beta*(T-To)<<1

I was wondering what numerical value this would be? For my model this value is .34. Do you think the B-approx would be valid? Thanks

Re: boussinesq approx
 

Also, referring to To, the operating temperature. In my model, the temperature increases from the inlet to the outlet. Would a good value of my operating temperature be the average? Thanks

Re: boussinesq approx
 

Hi

When using bousinessq approximation the Beta*(T-To)<<1

value is valid for your problem only when the temperature differences in the domain are large but cannot be used with species calculations, combustion, or reacting flows.

Please note that the beta values are generally very small for the fluid you are considering and in that case you generally do not even approach a value of even 0.01 So kindly check your beta value once again .