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Heat and Moisture solver - Neumann time varing BC

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Old   August 6, 2013, 10:44
Default Heat and Moisture solver - Neumann time varying BC
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Richard
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I would like to write solver for Heat and Moisture transfer in material, but I have problem with boundary conditions. I am using groovyBC to calculate heat and vapour flux on boundaries, but for moisture field it causes stability problems in results.

I can not find problem, but I am thinking about orders of number, heat gradient is in 1e01 but vapour gradient is in 1e-10

Heat transfer flux is obtained from q=alpha*temperature_difference (alpha values from 5 to 30) temperature difference less then 10 Kelvins.

Vapour flux is obtained from q=beta*partial_pressure_difference (beta about 1e-10, partial pressure difference less than 800Pa)

It works for steady state for Dirichlet and Neuman boundary condition.
Where could be a problem?

Thanks
Richard

Last edited by Ricardo; August 6, 2013 at 14:06.
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Old   August 6, 2013, 14:13
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Richard
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Please delete this topic, problem was not in solver...
I used wrong aproximation of sorption curve (dw) in fvm::ddt(dw,F)... and it caused oscilation of solution

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Richard
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