Two PDEs that need to solved alternatively

Anish Kumar Kodyingal

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Hi,

I am trying to solve the Poisson-Nernst-Planck (PNP) equation:

This is not the real set of equations I am solving. This is where I am starting. The idea is that the solver for eqn 1 must step through time and at each step solver for eqn 2 will take input from the time step of eqn 1 and solve for phi. Thus, the overall solver for conc must step through time from 0 to 1s but at each point the Poisson eqn 2 must be solved to get the potential.

How do i achieve this? I have attached the file to give an idea of the equations and methods I am using. The concentration updates correctly at each time step however the eqn 2 does not evolve over time. Can someone help me with this? any help will be greatly appreciated!



2 Replies Last Post Jun 12, 2024, 4:04 p.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 5 months ago Jun 6, 2024, 10:42 a.m. EDT
Updated: 5 months ago Jun 6, 2024, 10:43 a.m. EDT

Solve both equations in a single, time-dependent, solution step. See the attached file.

Jeff

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Jeff Hiller
Solve both equations in a single, time-dependent, solution step. See the attached file. Jeff


Anish Kumar Kodyingal

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Posted: 5 months ago Jun 12, 2024, 4:04 p.m. EDT

Hi Jeff,

Thank you so much for your swift response and help! You are an absolute life saver it works now. Appreciate your help :)

Hi Jeff, Thank you so much for your swift response and help! You are an absolute life saver it works now. Appreciate your help :)

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