In the limit of zero capillary pressure, solutions to the equations governing three-phase flow, obtained using common empirical relative permeability models, exhibit complex wavespeeds for certain saturation values (elliptic regions) that result in unstable and non-unique solutions. We analyze a simple but physically realizable pore-scale model: a bundle of cylindrical capillary tubes, to inves...

We present a model order reduction approach for parametrized laminar flow problems including viscous boundary layers. The viscous effects are captured by the incompressible NavierStokes equations in the vicinity of the boundary layer, whereas a potential flow model is used in the outer region. By this, we provide an accurate model that avoids imposing the Kutta condition for potential flows as ...

An analytical study of the flow induced by vibrating solid boundaries is presented. A Newtonian viscous fluid confined in an infinite channel with flexible walls is considered. The analysis is primarily motivated by the need for efficient mixing of highly viscous fluids. Transverse motions in the form of standing waves vibrated at small amplitudes are considered and the governing equations are ...

Adsorption of proteins onto membranes can alter the local membrane curvature. This phenomenon has been observed in biological processes such as endocytosis, tubulation, and vesiculation. However, it is not clear how the local surface properties of the membrane, such as membrane tension, change in response to protein adsorption. In this article, we show that the partial differential equations ar...

We demonstrate that the processing of the experimental data for the average velocity profiles obtained by J. M. ¨ Osterlund 1 ] was incorrect. Properly processed these data lead to the opposite conclusion: they confirm the Reynolds-number-dependent scaling law and disprove the conclusion that the flow in the intermediate ('overlap') region is Reynolds-number-independent. 1 In a recent issue of ...

We demonstrate that the processing of the experimental data for the average velocity profiles obtained by J. M. ¨ Osterlund (www.mesh.kth.se/∼jens/zpg/) presented in [ 1 ] was incorrect. Properly processed these data lead to the opposite conclusion: they confirm the Reynolds-number-dependent scaling law and disprove the conclusion that the flow in the intermediate ('overlap') region is Reynolds...

Capillary instability of a viscous fluid cylinder of diameter D surrounded by another fluid is determined by a Reynolds number J = V D `= `, a viscosity ratio m = a= ` and a density ratio ` = a= `. Here V = = ` is the capillary collapse velocity based on the more viscous liquid which may be inside or outside the fluid cylinder. Results of linearized analysis based on potential flow of a viscous...