Three problems in microfluidics: Electrokinetic instability, electrohydrodynamic self-assembly, and slipPublic Deposited
This thesis deals with three problems encountered in micro- and nano-fluidics: linear stability analysis of electrokinetic mixing in icrochannels, development of a general purpose numerical technique for fully resolved simulation of electrohydrodynamic particulate flows, and studying the phenomenon of molecular scale slip next to boundaries in micro- and nano-channels. Mixing in microscale devices is not easy due to the laminar flow conditions. Hence, various strategies are being proposed to mix fluids in microfluidic devices. One such approach is based on so-called electrokinetic instabilities. Self-assembly can be an important means for micro/nanoscale fabrication. A fundamental understanding of this process is still missing. Such an understanding could help in developing better strategies to obtain optimal deposition pattern. One part of this thesis is focused on developing a fundamental numerical tool to investigate such problems. In continuum fluid dynamics, the no-slip boundary condition is typically used. However, slip is typically reported in small scale devices. Slip can be helpful to reduce the flow resistance and thus reduce the energy requirement in micro- and nanochannels. In this thesis it is explored whether it is possible to reproduce molecular scale slip behavior through continuum equations. This approach leads to insights into the mechanism of slip in the context of continuum equations. It could also be useful in developing multiscale computational techniques.