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- - **Heat and Moisture solver - Neumann time varing BC**
(*http://www.cfd-online.com/Forums/openfoam-programming-development/121848-heat-moisture-solver-neumann-time-varing-bc.html*)

Heat and Moisture solver - Neumann time varying BCI 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?:confused: Thanks Richard |

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 :) Thanks Richard |

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