Effect of an external force on the by-pass transition mechanism in internal flows electrical double layer effect in mini and micro channels

The effect of the electric double layer (EDL) on the bypass transition mechanism is explored through direct numerical simulations. The electrokinetic effects destabilize rapidly the flow when the local disturbance and/or the Reynolds number are respectively strong and large enough to overcome the transient growth regime. It is found that a weak perturbation quickly leads to the transition through bypass and non-linear interactions under the EDL effect, while an order of magnitude larger disturbance is incapable to destabilize the macro-scale flow. The EDL develops some new transitional wall structures during the bypass process. It is concluded that electrostatic effects can be efficiently used to enhance the mixing and heat transfer in microchannels, providing that the diffuse layer is large enough.