From the above figure,
∇.(∇∅)=0
i.e.
Given boundary conditions:
$\displaystyle \displaystyle \frac{\partial \varphi}{\partial n} = 0$ (normal direction)
$\displaystyle \varphi=0 $ at grounded electrode
$\displaystyle \varphi=\varphi( t)$ at upper electrode
Now how can I solve?
I have tried as follows using separation of variable-
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