Hele-Shaw flow

About: Hele-Shaw flow is a research topic. Over the lifetime, 5451 publications have been published within this topic receiving 151320 citations.

Turbulent liquid flow down vertical walls

Abstract: Photoggraphic methods have been used to study the behavior of water flowing freely down vertical surfaces under the influence of gravity at Reynolds numbers between 200 and 30,000. The physical appearances of the liquid layers in transitional and fully turbulent flow have been noted. Layer thicknesses have been obtained from high-speed photographs and correlated with liquid Reynolds numbers, the range of experimental data thus being extended into the fully turbulent region. A simple basis of comparison with flow between parallel plates has been developed.

Electrokinetically-driven non-Newtonian fluid flow in rough microchannel with complex-wavy surface

Abstract: A numerical investigation is performed into the flow characteristics of electrokinetically-driven non-Newtonian fluids in rough microchannels with a complex-wavy surface. In performing the simulations, the flow behavior of the non-Newtonian fluids is characterized using a power-law model and the complex-wavy surface is modeled via the superimposition of two sinusoidal functions. The simulations examine the respective effects of the flow behavior index, the non-dimensional Debye–Huckel parameter, and the complex wavy-surface geometry parameters on the flow field characteristics, volumetric flow rate and electric field intensity. The results show that the flow behavior of non-Newtonian fluids is significantly dependent on the value of the flow behavior index in the power-law model. Specifically, the volumetric flow rate increases as the flow behavior index reduces. For a pseudoplastic fluid, the volumetric flow rate increases with an increasing value of the non-dimensional Debye–Huckel parameter due to the corresponding reduction in viscosity. By contrast, for a dilatant fluid, the volumetric flow rate reduces as the Debye–Huckel parameter increases. Finally, it is shown that the velocity profile near the complex wavy surface is more sensitive to changes in the waveform geometry than that in the center of the channel. Overall, the results presented in this study provide a useful insight into the manipulation of non-Newtonian fluids within real-world microchannels characterized by surface roughness.

Visualization of three-dimensional flow in a four-roll mill

Abstract: Flow visualization has been used to study the motion of a Newtonian fluid in a four-roll mill. Observations of the effect of increasing Reynolds number on the evolution of steady three-dimensional flow between the rollers are reported. The flow visualization experiments have been conducted for two values of the aspect ratio (defined as the ratio of roller length to gap width between rollers). The rollers have been constrained to rotate in a manner which generates an approximately two-dimensional pure extensional flow near the center of the apparatus at low speeds. Steady, symmetrically positioned vortices grow near the top and bottom walls of the container as the Reynolds number is increased up to a critcal value. An increase in Reynolds number beyond this critical value results in a loss of symmetry in the flow pattern. The nature of this transition is strongly dependent upon the aspect ratio.