Velocity profiles of fluid flow close to a hydrophobic surface

Abstract

Abstract:The results of research on viscous liquid flow upon a superhydrophobic surface are presented in the paper. In the introduction, the degrees of surface hydrophobicity in correlation with an adhesion coefficient are defined. The usage of the adhesion coefficient for the definition of a new boundary condition is employed for expressing the slip of the liquid over the superhydrophobic surface. The slip of the liquid was identified on a special experimental device. The essence of the device consists of a tunnel of rectangular cross section whose one wall is treated with a superhydrophobic layer. The other walls are made of transparent organic glass whose surface is hydrophilic. Velocity profiles are measured by PIV. The methodology is drawn so that it allows the speed determination at the closest point to the wall. The measurements were performed for different Reynolds numbers for both laminar and turbulent flow. Based on the measured velocity profiles, marginal terms of use have been verified, expressing slippage of the liquid on the wall. New forms of velocity profiles considering superhydrophobic surfaces are shown within the work.

The significance of growth shells in development of symmetry, transparency, and refraction of the human lens

“…Studies of microfluidity suggest the opposite effect ( 76 – 79 ). High cholesterol can stabilize membranes, increase hydrophobicity to decrease surface tension, and help move fluids through the microcirculation of the lens ( 80 ). The complexity and heterogeneity of fiber membranes and their microenvironment make the study of microcirculation a challenge.…”

“…When the space between cell membranes decreases, the resistance to turbulent flow can decrease to favor laminar flow, increasing microfluidity ( 77 , 79 ). The microfluidity between membranes can be enhanced further by an increase in the area of hydrophobic surface, reducing interactions between aqueous fluid and charged membrane phospholipids ( 80 ). Increased membrane cholesterol resists oxygen permeability favoring elimination of intracellular organelles ( 81 , 82 ) and stabilizes the elongated fiber shape, the condensation of the cytoskeleton at the cell periphery, the establishment of transparent short range order, phospholipid surface projections, and a decrease the intercellular spaces ( 83 – 85 ).…”

Experimental Investigation of the Effect of Hydrophobic Surfaces On Friction Losses in Turbulent Pipe Flows

“…Fiolava vd. [24] hidrofobik malzeme ile kaplı paralel plakalar arasındaki laminer akım için duvardaki kayma koşulunu ve buna bağlı olarak oluşan hız profilini incelemişlerdir. Başka bir çalışmalarında [25] hidrofilik ve süperhidrofobik yüzeylerdeki hız profilini PIV tekniği ile incelemişlerdir.…”

Particle Imaging Velocimetry Measurement of Air Flow Between High Voltage Asymmetrical Electrodes

“…It is a precise contactless measuring method with minimal invasiveness and with flexible measuring range including the velocities we expect in our experiment. Last but not least it is also available at Technical university of Liberec and our laboratory has a long-time practical experience with it [6,7].…”