Discussion Forum

Dear all,
I’ve been trying to rebuild Green’s 2D AC-electroosmosis model on comsol.

I use the weak form mode(w) to solve the laplace equation with pde boundary conditions.

The results of electric field are what i expected but the fluid field velocities are zero everywhere.

(1) The models i use:

Weak Form PDE(w) & Laminar flow(spf)


(2) The equations of the Weak Form PDE(w) model:

 (i) Weak form equation: weak = -test(phix)*phix-test(phiy)*phiy

 (ii) Weak contribution(on electrodes): -(i*ω*C/σ)*test(phi)*(phi-V)



test(phi) is the test function for electric potential “phi”

test(phix) is the test function for tangential electric field “phix”


(3) The boundary condition of the Laminar flow(spf) model:

Slip Velocity (on electrodes)

u = u_slip = -(eΛ/4η)*pd(abs(phi-V)^2, x)






The equations are derived from Green’s article.

Any advice for solving the fluid field problem would be great.
Thanks for your attention.




Reference:
N. G. Green, A. Ramos, A. González, H. Morgan, and A. Castellanos,

Phys. Rev. E 66, 026305 – Published 19 August 2002.

journals.aps.org/pre/abstract/10.1103/PhysRevE.66.026305