Shear-Driven Flow

Couette flow is shear-driven flow, as opposed to pressure-driven. In this instance, two parallel plates, separated by a distances h, are sheared relative to one another. The motion induces shear in the interstitial fluid, generating a linear velocity profile that depends on the motion of the moving surface. If we assume a linear shear rate, the shear stress is given simply by... 

Desmet, G., Baron, G. V., Chromatographic explanation for the side-wall induced band braodening in pressure-driven and shear-driven flows through cannels with high aspect-ration rectangular cross-section./. Chromatogr. A 2002, 946, 51-58. 

Nanoscale gas transport Shear-driven flow Surface force effects Tangential momentum accommodation coefficient... 

Argon gas flow confined between two infinite plates that are a distance H apart is considered as illustrated in Fig. 2. Periodic boundary conditions are applied in the axial (x) and lateral (z) directions. Shear-driven flow is obtained by moving the top and bottom channel walls in opposite directions with a characteristic velocity of Uw = Ms/ykbTjm where M is the Mach... 

The generation of a stable and controllable fluid flow in microfluidic devices is a major issue, and a lot of research work has been put into optimizing the flow driving methods. Not only conventional methods (derived from macroscopic applications) like pressure-driven and electroosmotic flows have been scaled down, but also novel methods like shear-driven flows (SDF) have been introduced. There are several problems associated with the conventional flow driving methods pressure-driven flows suffer from pressure drop limitations, while electroosmotic flows suffer from Joule heating, fluctuations of flow velocity, and double-layer overlap [1]. Therefore, other approaches to evade these problems and limitations have been proposed (centrifugal forces, magnetohydrodynamic forces, etc.). 

Tchikanda SW, NHson RH, Griffiths SK (2004) Modeling of piessuie and shear-driven flows in open rectangular microchannels, Int. J. Heat and Mass Transfer 47 527—538... 

Couette flow can be used as a prototype flow to model shear-driven flows such as micromotor, microbearing, and so on. As the flow is shear driven, the pressure does not change in the stream-wise direction. The compressibility effects may be important for large temperature fluctuations or at high speed. Let us consider an incompressible Couette flow with slip (Figure 3.12). 

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