Measurement of Newtonian fluid slip using a torsional ultrasonic oscillator

Willmott, Geoff R.; Tallon, J. L.

doi:10.1103/physreve.76.066306

Cited by 22 publications

(14 citation statements)

References 59 publications

(159 reference statements)

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“…The relationship between the bulk viscosity and the slip length was previously introduced as b = η/k, where friction k is an interfacial property [26]. However, recent experimental studies have revealed the significant influence of an apparent viscosity on capillary filling speed [4,27].…”

Section: Introductionmentioning

confidence: 99%

Near-surface viscosity effects on capillary rise of water in nanotubes

Barışık

Kim

2015

Phys. Rev. E

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In this paper, we present an approach for predicting nanoscale capillary imbibitions using the Lucas-Washburn (LW) theory. Molecular dynamics (MD) simulations were employed to investigate the effects of surface forces on the viscosity of liquid water. This provides an update to the modified LW equation that considered only a nanoscale slip length. An initial water nanodroplet study was performed to properly elucidate the wetting behavior of copper and gold surfaces. Intermolecular interaction strengths between water and corresponding solid surfaces were determined by matching the contact angle values obtained by experimental measurements. The migration of liquid water into copper and gold capillaries was measured by MD simulations and was found to differ from the modified LW equation. We found that the liquid layering in the vicinity of the solid surface induces a higher density and viscosity, leading to a slower MD uptake of fluid into the capillaries than was theoretically predicted. The near-surface viscosity for the nanoscale-confined water was defined and calculated for the thin film of water that was sheared between the two solid surfaces, as the ratio of water shear stress to the applied shear rate. Considering the effects of both the interface viscosity and slip length of the fluid, we successfully predicted the MD-measured fluid rise in the nanotubes.

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Section: Introductionmentioning

confidence: 99%

Near-surface viscosity effects on capillary rise of water in nanotubes

Barışık

Kim

2015

Phys. Rev. E

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“…Under these conditions, the leading order non-dimensional rotor and stator velocity boundary conditions given in (5) and 6, respectively, become…”

Section: Deterministic Mathematical Modelmentioning

confidence: 99%

“…However experimental studies examining specific chemical and electrochemical conditions of both the solid and liquid showed slip velocities can exist, which are attributed to the effect of the extra reactions on the wettability of the liquid and the potential absorption into the solid surface [13,14]. Typical experimental and theoretical studies on the existence of slip velocity at micro and nano scales, are given by [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Probability of Face Contact for a High-Speed Pressurised Liquid Film Bearing Including a Slip Boundary Condition

et al. 2015

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An initial deterministic mathematical model for the dynamic motion of a simple pressurised liquid film bearing is derived and utilised to evaluate the possibility of bearing contact for thin film operation. For a very thin film bearing the flow incorporates a Navier slip boundary condition as parametrised by a slip length that in general is subject to significant variability and is difficult to determine with precision. This work considers the formulation of a modified Reynolds equation for the pressurised liquid flow in a highly rotating coned bearing. Coupling of the axial motion of the stator is induced by prescribed axial oscillations of the rotor through the liquid film. The bearing gap is obtained from solving a nonlinear second-order non-autonomous ordinary differential equation, via a mapping solver. Variability in the value of the slip length parameter is addressed by considering it as a random variable with prescribed mean and standard deviation. The method of derived distributions is used to exactly quantify the impact of variability in the slip length with a parametric study investigating the effect of both the deterministic and distribution parameters on the probability of contact. Additionally, as the axial rotor oscillations also have a random aspect due to possible varying excitations of the system, the probability of contact is investigated for both random amplitude of the periodic rotor oscillations and random slip length, resulting in a two parameter random input problem. The probability of contact is examined to obtain exact solutions and evaluate a range of bearing configurations.

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“…Therefore, very large slip lengths of water flows obtained in CNT signify a considerable enhancement in water flow rates (Lee, Choi et al 2008). As the size of the nanotube decreases, the dynamics at its surface plays an increasingly important role (Willmott and Tallon 2007). For investigating the relationship between the slip length and the interfacial properties, it is useful to understand the slip length in connection of liquid-solid interface friction.…”

Section: Slip Length Theorymentioning

confidence: 99%