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Coupling of Electrostatics and Nerst plank equation

Hi,

I am trying to solve two equations simultaneously as follows

1) Div(Grad (V)) = - rho/eps

2) Div(D*Grad(C) - Z*u_m*F*C*Grad(V)) = 0

where V is voltage ,rho is space charge density, eps is permittivity of the material, D is the diffusion coefficient, C is the concentration of species (mol/m^3), Z is the charge number, u_m is the mobility coefficient and F is Faraday constant.
rho = F*C (C/m^3). I am using the default settings with UMFPACK coupled solver but I am not able to get any thing. The code returns the message "failed to find the solution". I think that the coupling seems to be simple.

Does any one have any experience of this kind ???

1 Reply Last Post Jan 16, 2013, 11:16 PM EST
Posted: 5 years ago Jan 16, 2013, 11:16 PM EST
I assume you are trying to simulate electrical double layer or related problem. Please check the consistency of units and boundary conditions. Sometimes scaled variables also helps in quick convergence.

How you are calculating your rho (volumetric space charge density)? are you calculating it or imposing it somehow?

Please post more information if you can not resolve your problem.

I assume you are trying to simulate electrical double layer or related problem. Please check the consistency of units and boundary conditions. Sometimes scaled variables also helps in quick convergence. How you are calculating your rho (volumetric space charge density)? are you calculating it or imposing it somehow? Please post more information if you can not resolve your problem.

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