Sliding Dynamics of a Water Droplet On Silicon Oil Film Surface

Abstract A sliding droplet over the silicon oil film is examined and the dynamics of droplet motion are explored. The solution crystallized wafer surfaces are silicon oil impregnated and the uniform thickness oil film is realized. A recording facility operating at high-speed and the tracker program are used to monitor and evaluate the droplet dynamics during droplet sliding. The sliding behavior and flow generated in the droplet fluid are predicted by adopting the experimental terms. Findings revealed that the crystallized surface possesses the texture composing of spherules and fibrils, which give rise to 132o ± 4o contact angle and 38o ± 4o hysteresis. Oil impregnation on the crystalized surface improves the optical transmittance by three times for 250 nm to 500 nm wavelength range and almost 1.5 times after 500 nm to 850 nm wavelengths of the optical spectrum. The oil rim and ridges are developed in sliding water droplet vicinity while influencing droplet motion; however, this influence is estimated as almost 12% of droplet gravitational energy change during sliding. A circulatory flow is developed inside the droplet fluid and the maximum velocity in the droplet fluid changes as the droplet location changes on the oil surface during its sliding.

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Sliding Water Droplet on Oil Impregnated Surface and Dust Particle Mitigation

Molecules ◽

10.3390/molecules26040789 ◽

2021 ◽

Vol 26 (4) ◽

pp. 789

Author(s):

Saeed Bahatab ◽

Bekir Sami Yilbas ◽

Abba Abdulhamid Abubakar ◽

Ghassan Hassan ◽

Anwaruddin Siddiqui Mohammed ◽

...

Keyword(s):

Dust Particle ◽

Water Droplet ◽

Film Surface ◽

Optical Transmittance ◽

Dust Particles ◽

Sliding Velocity ◽

Oil Film ◽

Silicon Oil ◽

Oil Impregnation ◽

Self Cleaning

Self-cleaning of surfaces becomes challenging for energy harvesting devices because of the requirements of high optical transmittance of device surfaces. Surface texturing towards hydrophobizing can improve the self-cleaning ability of surfaces, yet lowers the optical transmittance. Introducing optical matching fluid, such as silicon oil, over the hydrophobized surface improves the optical transmittance. However, self-cleaning ability, such as dust mitigation, of the oil-impregnated hydrophobic surfaces needs to be investigated. Hence, solution crystallization of the polycarbonate surface towards creating hydrophobic texture is considered and silicon oil impregnation of the crystallized surface is explored for improved optical transmittance and self-cleaning ability. The condition for silicon oil spreading over the solution treated surface is assessed and silicon oil and water infusions on the dust particles are evaluated. The movement of the water droplet over the silicon oil-impregnated sample is examined utilizing the high-speed facility and the tracker program. The effect of oil film thickness and the tilting angle of the surface on the sliding droplet velocity is estimated for two droplet volumes. The mechanism for the dust particle mitigation from the oil film surface by the sliding water droplet is analyzed. The findings reveal that silicon oil impregnation of the crystallized sample surface improves the optical transmittance significantly. The sliding velocity of the water droplet over the thick film (~700 µm) remains higher than that of the small thickness oil film (~50 µm), which is attributed to the large interfacial resistance created between the moving droplet and the oil on the crystallized surface. The environmental dust particles can be mitigated from the oil film surface by the sliding water droplet. The droplet fluid infusion over the dust particle enables to reorient the particle inside the droplet fluid. As the dust particle settles at the trailing edge of the droplet, the sliding velocity decays on the oil-impregnated sample.

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Environmental dust repelling from hydrophilic/hydrophobic surfaces under sonic excitations

Scientific Reports ◽

10.1038/s41598-020-76418-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Abba Abdulhamid Abubakar ◽

Bekir Sami Yilbas ◽

Hussain Al-Qahtani ◽

Ammar Alzaydi

Keyword(s):

Polyvinyl Chloride ◽

High Speed ◽

Excitation Frequency ◽

Film Surface ◽

Optical Transmittance ◽

Dip Coating ◽

Dust Particles ◽

Hydrophobic Surfaces ◽

Vibrational Characteristics ◽

Chloride Film

Abstract Dust repelling from transparent polyvinyl chloride film surface via sonic excitation is examined and dynamics of repelled (inflight) dust particles are analyzed. An experimental rig is designed and built to assess the vibrational characteristics of the polyvinyl chloride film at different frequencies of sonic excitation. A high speed recording system and tracking program are utilized monitoring and evaluating the dynamics of the inflight particles. The dynamics of inflight particles are also simulated numerically and the predictions are compared with those of the experimental data. In order to examine the influence of dust particle adhesion on the dynamics of the inflight particles, the polyvinyl chloride film surface is hydrophobized through dip coating by functionalized nano-silica particles. Improvement of the optical transmittance of the dust mitigated film is determined via outdoor tests. The findings demonstrate that sonic excitation repels the particles from the film surface and it is more pronounced at 64 Hz excitation frequency while demonstrating that sonic excitation can be used for dust removal from transparent surfaces. The mitigation via sonic excitation improves the optical transmittance of the dusty surface by 77%, which becomes more apparent for hydrophobic surfaces.

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Droplet Rolling and Spinning in V-Shaped Hydrophobic Surfaces for Environmental Dust Mitigation

Molecules ◽

10.3390/molecules25133039 ◽

2020 ◽

Vol 25 (13) ◽

pp. 3039

Author(s):

Mubarak Yakubu ◽

Bekir Sami Yilbas ◽

Abba A. Abubakr ◽

Hussain Al-Qahtani

Keyword(s):

3D Printing ◽

Water Droplet ◽

High Speed ◽

Recording System ◽

Functionalized Silica ◽

Plate Surface ◽

Hydrophobic Surfaces ◽

Droplet Motion ◽

Rolling Velocity ◽

Solution Crystallization

The motion of a water droplet in a hydrophobic wedge fixture was examined to assess droplet rolling and spinning for improved dust mitigation from surfaces. A wedge fixture composed of two inclined hydrophobic plates had different wetting states on surfaces. Droplet rolling and spinning velocities were analyzed and findings were compared with the experiments. A wedge fixture was designed and realized using a 3D printing facility and a high speed recording system was adopted to evaluate droplet motion in the wedge fixture. Polycarbonate sheets were used as plates in the fixture, and solution crystallization and functionalized silica particles coating were adopted separately on plate surfaces, which provided different wetting states on each plate surface while generating different droplet pinning forces on each hydrophobic plate surface. This arrangement also gave rise to the spinning of rolling droplets in the wedge fixture. Experiments were extended to include dust mitigation from inclined hydrophobic surfaces while incorporating spinning- and rolling droplet and rolling droplet-only cases. The findings revealed the wedge fixture arrangement resulted in spinning and rolling droplets and spinning velocity became almost 25% of the droplet rolling velocity, which agrees well with both predictions and experiments. Rolling and spinning droplet gave rise to parallel edges droplet paths on dusty hydrophobic surfaces while striations in droplet paths were observed for rolling droplet-only cases. Spinning and rolling droplets mitigated a relatively larger area of dust on inclined hydrophobic surfaces as compared to their counterparts corresponding to rolling droplet-only cases.

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Axial oil film rupture in high speed bearings due to the effect of the centrifugal force

International Journal of Multiphase Flow ◽

10.1016/s0301-9322(97)88587-4 ◽

1996 ◽

Vol 22 ◽

pp. 149

Author(s):

C Koeneke

Keyword(s):

Centrifugal Force ◽

High Speed ◽

Film Rupture ◽

Oil Film

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Experimental Investigation on Cavitation Characteristics of a Three-Groove Journal Bearing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.420.47 ◽

2013 ◽

Vol 420 ◽

pp. 47-50

Author(s):

Ying Yang ◽

Jing Hua Dai

Keyword(s):

Experimental Investigation ◽

High Speed ◽

Journal Bearing ◽

Rupture Zone ◽

Work Characteristics ◽

Oil Film ◽

Rotating Speed ◽

Clear Effect ◽

Supply Pressure

Under high and super-high speed, oil film of the journal bearing is easy to crack and then becomes cavitation. The existence of cavitation has an important effect on the work characteristics of the shaft. On the journal bearing experiment rig the cavitation characteristics of the three-groove journal beaing were studied. The influences of the shaft rotating speed and supply pressure on cavitation shape were investigated. The results show that rotating speed and supply pressure have a clear effect on the cavitation shape, and the number of cavitation strip in the rupture zone decreases when the supply pressure increases.

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Influence of oil film inertia on piston skirt lubrication in high speed engine

Journal of Shanghai University (English Edition) ◽

10.1007/s11741-003-0040-9 ◽

2003 ◽

Vol 7 (3) ◽

pp. 285-288

Author(s):

Fan-Ming Meng ◽

You-Yun Zhang

Keyword(s):

High Speed ◽

Oil Film ◽

Piston Skirt ◽

High Speed Engine ◽

Speed Engine

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Kinematics of Tongue Projection in Chamaeleo Oustaleti

Journal of Experimental Biology ◽

10.1242/jeb.159.1.109 ◽

1991 ◽

Vol 159 (1) ◽

pp. 109-133 ◽

Cited By ~ 10

Author(s):

PETER C. WAINWRIGHT ◽

DAVID M. KRAKLAU ◽

ALBERT F. BENNETT

Keyword(s):

High Speed ◽

Prey Capture ◽

Maximum Velocity ◽

Head Movements ◽

Florida State University ◽

State University ◽

Maximum Acceleration ◽

Related Family ◽

High Speed Cinematography ◽

Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

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Comparison of the fast-start performances of closely related, morphologically distinct threespine sticklebacks (Gasterosteus spp.)

Journal of Experimental Biology ◽

10.1242/jeb.199.12.2595 ◽

1996 ◽

Vol 199 (12) ◽

pp. 2595-2604 ◽

Cited By ~ 5

Author(s):

T Law ◽

R Blake

Keyword(s):

Angular Velocity ◽

High Speed ◽

High Performance ◽

Gasterosteus Aculeatus ◽

Morphological Characteristics ◽

Maximum Velocity ◽

Threespine Stickleback ◽

Biomechanical Study ◽

Maximum Acceleration ◽

Fast Start

Fast-start escape performances for two species of threespine stickleback, Gasterosteus spp., were investigated using high-speed cinematography (400 Hz). The two fishes (not yet formally described, referred to here as benthic and limnetic) inhabit different niches within Paxton Lake, British Columbia, Canada, and are recent, morphologically distinct species. All escape responses observed for both species were double-bend C-type fast-starts. There were no significant differences between the species for any linear or angular parameter (pooled averages, both species: duration 0.048 s, distance 0.033 m, maximum velocity 1.10 m s-1, maximum acceleration 137 m s-2, maximum horizontal angular velocity 473.6 rad s-1 and maximum overall angular velocity 511.1 rad s-1). Benthics and limnetics have the greatest added mass (Ma) at 0.3 and 0.6 body lengths, respectively. The maximum Ma does not include the fins for benthics, but for limnetics the dorsal and anal fins contribute greatly to the maximum Ma. The deep, posteriorly placed fins of limnetics enable them to have a fast-start performance equivalent to that of the deeper-bodied benthics. Both the limnetic and benthic fishes have significantly higher escape fast-start velocities than their ancestral form, the anadromous threespine stickleback Gasterosteus aculeatus, suggesting that the high performance of the Paxton Lake sticklebacks is an evolutionarily derived trait. In this biomechanical study of functional morphology, we demonstrate that similar high fast-start performance can be achieved by different suites of morphological characteristics and suggest that predation might be the selective force for the high escape performance in these two fishes.

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