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daol February 6, 2008 08:51

Boussinesq model gives constant density

I'm using the Boussinesq model for density for a natural convection problem with water. I've set the operating temperature and thermal expansion coefficient for water.

The temperature difference is a maximum of 25K but still the density contours are constant throughout the entire domain. However I do get a velocity field and the only driving force I have is buoyancy so there must be some density difference. Why can't I see it in reports or contours?

Regards Ola

S. Gatzka February 13, 2008 04:30

Re: Boussinesq model gives constant density
The Boussinesq-Approximation is applyed just to the buoyancy-expression in the navier-stokes-equations and not to the general density, which is treated as constant.

I experienced the same problem with a natural convection problem. The density was constant all over the area. But I got the right solution for the velocity-field. Therefore I suppose there is an other problem with your simulation.

Necmi Cevheri February 21, 2008 08:51

Re: Boussinesq model gives constant density
If you did not use a boundary layer in the vicinity of a wall, you may not observe those density gradients. Try meshing with a boundary layer in gambit

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