Wall-Driven Versus Pressure Gradient-Driven Flows in Porous Media

Statistical Estimates for Channel Flows Driven by a Pressure Gradient

Abstract. We present rigorous estimates for some physical quantities related to turbulent and non-turbulent channel flows driven by a uniform pressure gradient. Such results are based on the concept of stationary statistical solution, which is related to the notion of ensemble average for flows in statistical equilibrium. We provide a lower bound estimate for the mean skin friction coefficient ...

Bicritical instabilities in pressure driven helicoidal flows

This contribution presents new phenomena regarding the stability of pressure driven flows within annular pipes. The fluid is advected downstream due to an axial pressure gradient but also subjected to centrifugal mechanisms due to the independent rotation of the coaxial cylinders that contain it. Coexistence of upstream and downstream spiral secondary flows is observed in the co-rotating regime...

On-chip high-pressure picoliter injector for pressure-driven flow through porous media.

A high-pressure (> 3 MPa) on-chip injector has been developed for microchip applications including HPLC. The mechanical injector is implemented using in situ photopolymerization of fluorinated acrylates inside wet-etched silica microchips. The injector allows reproducible injections as small as 180 pL with < 250 ms duration. The injector operated robustly over 60 days and over 1000 injections. ...

Capillary Pressure Driven Water Movement in Wet Unsaturated Porous Media: Effect of Particle Electric Charge

Experimentos do fluxo da água usando um meio poroso não saturado compoto por diferentes sistemas de aalumina molhada não-saturada indicam que a carga superficial da partícula diminuiu com o aumento da água movimentada. O movimento máximo de água ocorreu quando a carga superficial era zero. O movimento da água foi afetado pela espessura da dupla camada elétrica no pH em que as partículas têm car...

High temperature and pressure reactive flows through porous media