Parametric numerical study of electrokinetic instability in cross-shaped microchannels

A multiblock in-house solver based on high-order accurate finite-difference schemes is developed to simulate electrokinetic instability (EKI) phenomena in realistic cross-shaped microchannels. Parametric numerical studies are systematically carried out to investigate the effects of different parameters on EKI including the conductivity ratio, the electric field strength, the channel depth, and the electric field ratios. Simulation results show that the solver has the capability to capture the threshold electric field for the onset of instabilities and it offers a good prediction for the critical features of EKI compared to the experiments presented in the literature. In addition, from the general parametric studies several useful guidelines are explored. Such guidelines can be applied to enhance the mixing efficiency in electrokinetic microdevices.