Rarefied gas flow in microtubes at low Reynolds numbers

Rarefied gas flow in microtubes at different inlet-outlet pressure ratios

Comments on flow through collapsible tubes at low Reynolds numbers.

A microfluidic rectifier: anisotropic flow resistance at low Reynolds numbers.

It is one of the basic concepts of Newtonian fluid dynamics that at low Reynolds number (Re) the Navier-Stokes equation is linear and flows are reversible. In microfluidic devices, where Re is essentially always low, this implies that flow resistance in microchannels is isotropic. Here we present a microfluidic rectifier: a microscopic channel of a special shape whose flow resistance is strongl...

Turbulent pipe flow at extreme Reynolds numbers.

Both the inherent intractability and complex beauty of turbulence reside in its large range of physical and temporal scales. This range of scales is captured by the Reynolds number, which in nature and in many engineering applications can be as large as 10(5)-10(6). Here, we report turbulence measurements over an unprecedented range of Reynolds numbers using a unique combination of a high-press...

Viscous Flow at High Reynolds Numbers

Let us first give a heuristic estimates of boundary layer in steady flows. Consider a particle near the wall to be influenced by viscosity. After traveling a distance x from the edge, it has been under viscous influence for a time of t = x/U . Let U be large. For finite x, t is small so that vorticity is spread sideways to the width (νt) ∼ (νx/U). Let us define this width to be the boundary lay...