One-charged-wall electro-osmotic channel
= One-charged-wall electro-osmotic channel
With $\psi(0)=\zeta$, $\psi\prime(d)=0$ and no slip at either wall, linear screening gives $\psi/\zeta=\cosh[\kappa(d-x)]/\cosh(\kappa d)$. The <velocity> is $v/U=1-(1-\operatorname{sech}\kappa d)x/d-\cosh[\kappa(d-x)]/\cosh(\kappa d)$. This electrically neutral-wall boundary assumes no external normal field; it differs from a grounded wall.