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Yu-Chen Shu

2009-05-22
12:00:00 - 14:00:00

Electro-osmotic flow in a micro-channel with corrugated walls:coherence between the electric potential and the wall shape function

308 , Mathematics Research Center Building (ori. New Math. Bldg.)

The electro-osmotic flow through a micro-channel with corrugated walls is studied under the Debye-Huckel approximation. An analytic solution by perturbation with appropriate averaging is carried out up to second order in terms of the small amplitude of corrugation. It is shown that the wavelength and phase difference of the corrugations can be utilized to control the flow relatively to the case of flat walls. In particular, for thick electric double layers the electro-osmotic flow can be enhanced significantly at long-wavelength corrugations because of the coherence between the electric potential and the wall shape function. Notably, these findings are not restricted to small amplitudes of corrugation at all. By applying the Ritz method to solve for the electro-osmotic flow, it is found that the enhancement becomes even more significant with increasing the amplitude of corrugation up to its maximum.