Film Formation and Flow Characteristics at the Inlet of a Starved Contact—Theoretical Study

1983 ◽  
Vol 105 (2) ◽  
pp. 178-185 ◽  
Author(s):  
D. Bonneau ◽  
J. Frene
Keyword(s):  
Surface Tension ◽  
Film Formation ◽  
Flow Characteristics ◽  
Integral Equation Method ◽  
Surface Velocity ◽  
Stress Distributions ◽  
New Interpretation ◽  
Inlet Zone ◽  
Hydrodynamic Effects ◽  
Effect Of Surface

The conditions of film formation are examined theoretically when starvation occurs. The analysis is for two-dimensional Newtonian flow and includes surface tension effects. Using an integral equation method, stream function solutions, velocity fields, pressure and shear stress distributions are calculated along and across the inlet zone of a sliding contact. The effect of surface tension and feeding thickness on the meniscus shape and on pressure buildup is studied in correlation with hydrodynamic effects. In all cases, pressure value lower than the gas pressure acting on the free boundary is found along the sliding surface. This depression value increases with an increase in viscosity or surface velocity. Owing to these results, a new interpretation of some published experimental data on starved contacts is proposed.

F41 Effect of Surface Tension on Gas-liquid Two-phase Flow Characteristics in Horizontal Mini-channels

2007 ◽  
Vol 2007.60 (0) ◽  
pp. 217-218
Author(s):  
Masatoshi MATSUO ◽  
Kazuhiro HORITA ◽  
Michio SADATOMI ◽  
Akimaro KAWAHARA
Keyword(s):  
Surface Tension ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase ◽  
Mini Channels ◽  
Effect Of Surface

DECOUPLING THE EFFECT OF SURFACE TENSION AND VISCOSITY ON SPRAY CHARACTERISTICS UNDER DIFFERENT AMBIENT PRESSURES: NEAR-NOZZLE BEHAVIOR AND MACROSCOPIC CHARACTERISTICS

2019 ◽  
Vol 29 (7) ◽  
pp. 629-654
Author(s):  
Zehao Feng ◽  
Shangqing Tong ◽  
Chenglong Tang ◽  
Cheng Zhan ◽  
Keiya Nishida ◽  
...  
Keyword(s):  
Surface Tension ◽  
Spray Characteristics ◽  
Effect Of Surface

Surfactant Impurities Can Explain the Jones-Ray Effect

2018 ◽  
Author(s):  
Timothy Duignan ◽  
Marcel Baer ◽  
Christopher Mundy
Keyword(s):  
Surface Tension ◽  
Electrostatic Potential ◽  
Driving Forces ◽  
Salt Water ◽  
Fundamental Property ◽  
Apparent Contradiction ◽  
Low Salt ◽  
Air Water Interface ◽  
Added Salt ◽  
Effect Of Surface

<div> <p> </p><div> <div> <div> <p>The surface tension of dilute salt water is a fundamental property that is crucial to understanding the complexity of many aqueous phase processes. Small ions are known to be repelled from the air-water surface leading to an increase in the surface tension in accordance with the Gibbs adsorption isotherm. The Jones-Ray effect refers to the observation that at extremely low salt concentration the surface tension decreases in apparent contradiction with thermodynamics. Determining the mechanism that is responsible for this Jones-Ray effect is important for theoretically predicting the distribution of ions near surfaces. Here we show that this surface tension decrease can be explained by surfactant impurities in water that create a substantial negative electrostatic potential at the air-water interface. This potential strongly attracts positive cations in water to the interface lowering the surface tension and thus explaining the signature of the Jones-Ray effect. At higher salt concentrations, this electrostatic potential is screened by the added salt reducing the magnitude of this effect. The effect of surface curvature on this behavior is also examined and the implications for unexplained bubble phenomena is discussed. This work suggests that the purity standards for water may be inadequate and that the interactions between ions with background impurities are important to incorporate into our understanding of the driving forces that give rise to the speciation of ions at interfaces. </p> </div> </div> </div> </div>

scholarly journals The effect of surface tension on steadily translating bubbles in an unbounded Hele-Shaw cell

2017 ◽  
Vol 473 (2201) ◽  
pp. 20170050 ◽  
Author(s):  
Christopher C. Green ◽  
Christopher J. Lustri ◽  
Scott W. McCue
Keyword(s):  
Surface Tension ◽  
Numerical Solutions ◽  
Bubble Velocity ◽  
Number Of Solutions ◽  
Branch Number ◽  
Single Solution ◽  
Countably Infinite ◽  
Prime Function ◽  
Hele Shaw Cell ◽  
Effect Of Surface

New numerical solutions to the so-called selection problem for one and two steadily translating bubbles in an unbounded Hele-Shaw cell are presented. Our approach relies on conformal mapping which, for the two-bubble problem, involves the Schottky-Klein prime function associated with an annulus. We show that a countably infinite number of solutions exist for each fixed value of dimensionless surface tension, with the bubble shapes becoming more exotic as the solution branch number increases. Our numerical results suggest that a single solution is selected in the limit that surface tension vanishes, with the scaling between the bubble velocity and surface tension being different to the well-studied problems for a bubble or a finger propagating in a channel geometry.

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