Is free surface free in micro-scale electrokinetic flows?
When a rigid boundary is replaced by a free surface, or by a liquid-liquid interface, the shear stress is reduced near the boundary because the no-slip on the rigid boundary is relaxed. A nonzero fluid velocity exists on the free surface, and the flow rate would increase by the replacement. For electrokinetic flows, however, the replacement from rigid to free boundary can lead to an increase (decrease) in shear stress (flow rate). This counterintuitive effect of free surface is presented in this note for a generic electroosmotic flow in a microchannel.
Choi
WooSeok
W
Department of Mechanical Engineering, POSTECH, Pohang, Republic of Korea.
Sharma
Ashtosh
A
Qian
Shizhi
S
Lim
Geunbae
G
Joo
Sang Woo
SW
D003198:Computer Simulation; D053841:Electroosmosis; D007700:Kinetics; D044085:Microfluidics; D033081:Shear Strength; D012996:Solutions / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013816:Thermodynamics
D012996:Solutions; D012997:Solvents