scholarly journals Dynamics of a water droplet on a hydrophobic inclined surface: influence of droplet size and surface inclination angle on droplet rolling

RSC Advances ◽  
2017 ◽  
Vol 7 (77) ◽  
pp. 48806-48818 ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Abudllah Al-Sharafi ◽  
Haider Ali ◽  
Nasser Al-Aqeeli
Keyword(s):  
Droplet Size ◽  
Inclination Angle ◽  
Water Droplet ◽  
Dust Particles ◽  
Dynamic Motion ◽  
Surface Inclination ◽  
Inclined Surface

An understanding of the dynamic motion of a water droplet is critical to reduce the effort required to remove dust particles from such surfaces.

scholarly journals A water droplet-cleaning of a dusty hydrophobic surface: influence of dust layer thickness on droplet dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ghassan Hassan ◽  
Bekir S. Yilbas ◽  
Saeed Bahatab ◽  
Abdullah Al-Sharafi ◽  
Hussain Al-Qahtani
Keyword(s):  
Layer Thickness ◽  
Inclination Angle ◽  
Water Droplet ◽  
High Speed ◽  
Small Volume ◽  
Transition Period ◽  
Imaging System ◽  
Hydrophobic Surface ◽  
Dust Layer ◽  
Surface Inclination

Abstract Water droplet cleaning of a dusty hydrophobic surface is examined. Environmental dust are used in the experiments and cloaking velocity of a dust layer by a droplet fluid is measured and hemi-wicking conditions for the dust layer are analyzed adopting the pores media wick structure approach. A droplet motion on dusty and inclined hydrophobic surface is analyzed using a high speed digital imaging system. Influences of dust layer thickness, droplet volume, and surface inclination angle on the mechanisms of dust removal by a rolling droplet are evaluated. The findings revealed that dust cloaking velocity decreases exponentially with time. The droplet fluid can cloak the dust layer during its transition on the dusty surface. The transition period of droplet wetted length on the dusty surface remains longer than the cloaking time of the dust layer by the droplet fluid. Translational velocity of rolling droplet is affected by the dust layer thickness, which becomes apparent for small volume droplets. Small volume droplet (20 µL) terminates on the thick dust layer (150 µm) at low surface inclination angle (1°). The quantity of dust picked up by the rolling droplet increases as the surface inclination angle increases. The amount of dust residues remaining on the rolling droplet path is relatively larger for the thick dust layer (150 µm) as compared to its counterpart of thin dust layer (50 µm).

Detection of Water Droplet Size and Anion Species by Nonlinear Optical Scattering

1987 ◽  
Vol 4 (1-4) ◽  
pp. 85-89 ◽  
Author(s):  
Johannes H. Eickmans ◽  
Shi-Xiong Qian ◽  
Richard K. Chang
Keyword(s):  
Droplet Size ◽  
Water Droplet ◽  
Nonlinear Optical ◽  
Optical Scattering ◽  
Anion Species

scholarly journals Kinematic Strategies in Newly Walking Toddlers Stepping Over Different Support Surfaces

2010 ◽  
Vol 103 (3) ◽  
pp. 1673-1684 ◽  
Author(s):  
Nadia Dominici ◽  
Yuri P. Ivanenko ◽  
Germana Cappellini ◽  
Maria Luisa Zampagni ◽  
Francesco Lacquaniti
Keyword(s):  
Degrees Of Freedom ◽  
Walking Speed ◽  
Search Space ◽  
Systematic Change ◽  
Support Surface ◽  
Coordination Pattern ◽  
Surface Conditions ◽  
Surface Inclination ◽  
Support Surfaces ◽  
Inclined Surface

In adults, locomotor movements are accommodated to various support surface conditions by means of specific anticipatory locomotor adjustments and changes in the intersegmental coordination. Here we studied the kinematic strategies of toddlers at the onset of independent walking when negotiating various support surface conditions: stepping over an obstacle, walking on an inclined surface, and on a staircase. Generally, toddlers could perform these tasks only when supported by the arm. They exhibited strategies very different from those of the adults. Although adults maintained walking speed roughly constant, toddlers markedly accelerated when walking downhill or downstairs and decelerated when walking uphill or upstairs. Their coordination pattern of thigh–shank–foot elevation angles exhibited greater inter-trial variability than that in adults, but it did not undergo the systematic change as a function of task that was present in adults. Thus the intersegmental covariance plane rotated across tasks in adults, whereas its orientation remained roughly constant in toddlers. In contrast with the adults, the toddlers often tended to place the foot onto the obstacle or across the edges of the stairs. We interpret such foot placements as part of a haptic exploratory repertoire and we argue that the maintenance of a roughly constant planar covariance—irrespective of the surface inclination and height—may be functional to the exploratory behavior. The latter notion is consistent with the hypothesis proposed decades ago by Bernstein that, when humans start to learn a skill, they may restrict the number of degrees of freedom to reduce the size of the search space and simplify the coordination.

Effect of Surface Inclination on Filmwise Condensation Heat Transfer During Flow of Steam–Air Mixtures

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Abhinav Bhanawat ◽  
Mahesh Kumar Yadav ◽  
Maneesh Punetha ◽  
Sameer Khandekar ◽  
Pavan K. Sharma
Keyword(s):  
Heat Transfer ◽  
Inclination Angle ◽  
Horizontal Surface ◽  
Condensation Heat Transfer ◽  
Experimental Program ◽  
Steam Condensation ◽  
Flat Plates ◽  
Surface Inclination ◽  
Pure Steam ◽  
Effect Of Surface

Abstract Empirical/semi-empirical correlations are available in the literature to quantify the effect of several major parameters, like bulk pressure, non-condensable gas mass fraction, and wall subcooling, on condensation heat transfer coefficient (HTC). However, despite numerous applications of condensation on inclined flat plates, there is a lack of understanding of the effect of surface inclination on condensation heat transfer. Accordingly, a dedicated experimental program was undertaken to investigate the effect of surface inclination angle on filmwise steam condensation. Experiments were performed at different bulk pressures (1.7–4.2 bar absolute) and steam-air mass fractions (ranging from pure steam, i.e., 0% to 40% w/w air), with the steam-air mixture flowing over a flat test plate (Re range, 4200–4800). In each run, the inclination angle of the test surface was varied from −90 deg (condensation underneath the horizontal surface, facing downward) to +90 deg (condensation over the horizontal surface, facing upward) in increments of 15–20 deg (inclination angle θ measured from vertical). The results reveal an intriguing trend: for pure steam condensation, the HTCs decrease as the plate is inclined in either direction from the vertical, and the variation is nearly symmetric for both upward- and downward-facing configurations. On the other hand, for steam condensation in the presence of air, the HTCs decrease monotonically for upward-facing configurations, while they increase slightly (10–20%), and decrease subsequently (for θ < −70 deg) for downward-facing cases. Finally, the HTCs for inclined orientations are compared with the HTC in the standard vertical configuration to quantify the effect of inclination angle.

scholarly journals Correction: Water droplet on inclined dusty hydrophobic surface: influence of droplet volume on environmental dust particles removal

RSC Advances ◽  
2019 ◽  
Vol 9 (13) ◽  
pp. 7276-7276 ◽  
Author(s):  
Ghassan Hassan ◽  
Bekir Sami Yilbas ◽  
Abdullah Al-Sharafi ◽  
H. Al-Qahtani ◽  
Nasser Al-Aqeeli
Keyword(s):  
Water Droplet ◽  
Hydrophobic Surface ◽  
Dust Particles ◽  
Droplet Volume

Correction for ‘Water droplet on inclined dusty hydrophobic surface: influence of droplet volume on environmental dust particles removal’ by Ghassan Abdelmagid et al., RSC Adv., 2019, 9, 3582–3596.

A numerical model for estimation of water droplet size in the anode channel of a proton exchange membrane fuel cell

2019 ◽  
Vol 26 ◽  
pp. 101021 ◽  
Author(s):  
Kazem Mohammadzadeh ◽  
Bahare Jahani Kaldehi ◽  
Ramin Jazmi ◽  
Hassan Khaleghi ◽  
Reza Maddahian ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Numerical Model ◽  
Droplet Size ◽  
Water Droplet ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Exchange Membrane
Sign in / Sign up

Export Citation Format

Share Document