Finally there is a drop at the capillary region down to almost zero (note that zero on the graph is not zero pressure, it is equal to one atmospheric pressure of 760mm of Hg). Pressure differences are the driving force for flow through the circulatory system:the higher pressure in the aorta drives flow into the lower pressure regions:to arteriole and then to capillary. A computational study of two-phase viscoelastic systems in periodically constricted capillary tubes and found that drop deformation is enhanced by visco-elasticity irrespective of which phase is elastic. Wu33 numerically investigated both buoyancy-driven and pressure-driven motions of viscoelastic drop in a capillary tube. He found that elasticity in the drop phase suppresses drop deformation.
Theory also predicts the capillary number of the bubble jump which, in conjunction with previous theoretical results, determines the time to snapoff of gas bubbles moving through constricted capillaries. Excellent agreement is found with existing experimental data for Ohnesorge numbers ranging from 5 × 10 3 to 0.3. Effect of Dynamics Surface Tension on the Motion of Foam Foam flow in porous media exhibits striking properties that have been found desirable in many practical undertakings. These properties have been identified as enhanced gas viscosity by virtue of liquid film rheology, and reduced relative gas permeability by virtue of gas trapping. Many previous works treated foam in porous media as bubble trains flowing in a bundle of constricted capillary tubes. Flow of OilWater Emulsion Through Constricted Capillary TubesJul 14, 2008 · The flow of oilinwater emulsions through a constricted capillary tube was analyzed by experiments and theory. The experiments consisted of flow visualization and pressure drop measurements of the flow. A number of different emulsions were prepared using synthetic oils and deionized water. The average drop size varied from smaller to larger than the neck radius.
Jun 01, 2018 · In turn, when just one drop is considered, the pressure drop increases as the drop flow in the upstream region, shows a single peak, which indicates the passage of the drop through the constriction, then decreases to an almost constant value as the drop flows through the narrow channel, and finally shows a sudden decrease when the drop reaches the exit of the constriction region. Implicit Multigrid Computations of Buoyant Drops The method is first validated for a freely rising drop in a straight channel, and it is then used to compute a freely rising drop in various constricted channels. Interaction of two buoyancy-driven drops in a continuously constricted channel is also presented. Measurements and simulation of liquid films during Dec 01, 2017 · Dynamics of the wetting fluid film in a constricted capillary tube The second part of the experiments examines the dynamics of wetting fluid films during snap-off events. Based on previous studies  ,  ,  ,  , to ensure the visualization of snap-off events, we chose constrictions with a ratio of the pore throat size to the pore
Dec 01, 2017 · Dynamics of the wetting fluid film in a constricted capillary tube The second part of the experiments examines the dynamics of wetting fluid films during snap-off events. Based on previous studies  ,  ,  ,  , to ensure the visualization of snap-off events, we chose constrictions with a ratio of the pore throat size to the pore Motion of a drop along the centreline of a capillary in a Estimates for the drop deformation at high capillary number are based on a simple model for annular flow and, in most cases, agree well with full numerical results if 1/2, in which case the drop elongation increases without limit as Ca increases. If < 1/2, the drop elongates towards a limiting non-zero cylindrical radius. Oscillatory flow of droplets in capillary tubes. Part 2 The motion of fluid droplets in constricted capillary tubes is investigated for flows subject to the combined action of a mean pressure gradient and an oscillatory body force. Numerical computations are employed to determine the effect of the oscillatory forcing on the mean flow rate and the mean droplet velocity.
The effect of contact angle on two-phase flow in capillary tubes. Dynamics of a drop in a constricted capillary tube. The effects of surfactant on the dynamics of bubble snap The effects of an insoluble surfactant on the motion of a drop or bubble as it is driven by a pressure gradient through a capillary tube is investigated numerically. We find that a drop in a straight capillary tube can either approach a steady-state shape or develop a re-entrant cavity at its rear. Viscosity and Laminar Flow; Poiseuilles Law PhysicsFor a given flow rate Q, the pressure drop will be greatest where the tube is most narrow. This is how water faucets control flow. Additionally, R is greatly increased by turbulence, and a constriction that creates turbulence greatly reduces the pressure downstream. Plaque in an artery reduces pressure and hence flow, both by its resistance and by the turbulence it creates.
Nov 02, 2009 · If gravity effects are negligible, the drop motion is determined by three independent parameters:the size a of the undeformed drop relative to the radius R of the capillary, the viscosity ratio between the drop phase and the wetting phase and the capillary number Ca, which measures the relative importance of viscous and capillary forces. We investigate the drop behaviour in the