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Instability mechanism based on Coriolis force, on a rapidly rotating portable device handling shear thinning fluids such as blood, is of utmost importance for eventual detection of diseases by mixing with the suitable reagents. Motivated by this proposition, the present study renders a modal stability analysis of shear thinning fluids in a rotating microchannel modelled by the Carreau rheological law. When a microchannel is engraved a rotating compact disc (CD) based device, the centrifugal force acts as the driving force that actuates the flow and the Coriolis force enhances the mixing process in significantly short span by destabilizing the flow. An OrrSommerfeld-Squire analysis is performed to explore the role of these forces on the linear stability of rotating shear-thinning flow. Reported results on shear thinning flow with streamwise disturbances indicate that the critical Reynolds number for the flow transition with viscosity perturbation is nearly half of that of the critical value for the same without viscosity perturbation. In sharp contrast, the present analysis considering spanwise disturbances reveals that the critical Reynolds numbers with and without viscosity perturbation remain virtually unaltered under rotational effects. However, the viscosity variation has no significant influence on the Coriolis force-based instability. Numerical results confirm that a momentous destabilization is possible by aid of the Coriolis force via generating secondary flow inside the channel. Interestingly, the roll cells corresponding to the instabilities at lower time constants exhibit the existence of two distinct vortices, and the centre of the stronger one is essentially settled towards the unstable stratified region. Moreover, for a higher value of the time constant, only one vortex occupies the entire channel.
In a shear flow particles migrate to their equilibrium positions in the microchannel. Here we demonstrate theoretically that if particles are inertial, this equilibrium can become unstable due to the Saffman lift force. We derive an expression for th
We present an experimental investigation of a novel low Reynolds number shear flow instability triggered by a chemical reaction. An acid-base reaction taking place at the interface between a Newtonian fluid and Carbopol-940 solution leads to a strong
Using a micro particle imaging velocity technique, we resolve for the first time the three dimensionnal structure of wormlike shear banding flows in straight microchannels. The study revealed two effects, which should be generic for shear banding flo
Exact solutions for laminar stratified flows of Newtonian/non-Newtonian shear-thinning fluids in horizontal and inclined channels are presented. An iterative algorithm is proposed to compute the laminar solution for the general case of a Carreau non-
Extremely small amounts of surface-active contaminants are known to drastically modify the hydrodynamic response of the water-air interface. Surfactant concentrations as low as a few thousand molecules per square micron are sufficient to eventually i