Impact of Coriolis force and Joule heating on the stability of electro-osmotic flow

We investigate the stability analysis on the combined influence of rotation and Joule heating of electrothermal flow in a microchannel confined between two infinitely long, parallel plates with constant zeta potential. Using the Debye–Hückel approximation, valid for dilute electrolytic solutions, we derive base-state solutions for electro-osmotic velocity, electric double-layer potential, and temperature distribution. A linear stability analysis is conducted using the Galerkin approximation method, and the critical conditions for flow instability are determined through marginal stability curves. Furthermore, we perform direct numerical simulations to visualize flow and temperature distributions in stable and unstable regimes. Our results reveal that both rotation and Joule heating play a crucial role in destabilizing the flow. Specifically, increasing the rotational parameter (Ro) induces secondary flows and Ekman-type layers, altering the classical plug-like electro-osmotic flow profile. Meanwhile, Joule heating generates temperature gradients and viscosity variations, further destabilizing the flow. These findings provide new insights into the stability of electro-osmotic flow systems, with implications for lab-on-a-chip devices, electrokinetic transport, and microfluidic thermal management.