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Natural Convection

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I am having trouble getting a a natural convection problem to converge, and I am just wondering if anyone could help me with understanding any possible reasons for it not converging (As I am reletively new to the software).

I am using fluid properties which are dependant on temperature, however the density variation with respect to temperature is very large over a large temperature difference, and i am wondering if this may be the problem, as I am using weakly compressible flow with general heat transfer modules on COMSOL 3.5a.

I know this is a general question, but any help would be greatly appreciated.

2 Replies Last Post 2010年7月20日 GMT-4 04:56

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Posted: 1 decade ago 2010年7月19日 GMT-4 17:57
Hi Mark,

Have you tried providing a point constraint on the pressure? I have found that to (sometimes) be necessary in convection problems.

Paul
Hi Mark, Have you tried providing a point constraint on the pressure? I have found that to (sometimes) be necessary in convection problems. Paul

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Posted: 1 decade ago 2010年7月20日 GMT-4 04:56
Thank you very much for your reply.

I did in fact set the point constraint for the pressure. That tripped me up at the begining. It turns out that it must be modelled using transient solver, and from the simulations I have ran, seems to be working fine. Very time consuming though.
Thank you very much for your reply. I did in fact set the point constraint for the pressure. That tripped me up at the begining. It turns out that it must be modelled using transient solver, and from the simulations I have ran, seems to be working fine. Very time consuming though.

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