Motion dynamics of a water drop located on a hydrophobic inclined surface under uniform airflow

Bastegani, Moshen; Bayareh, Morteza

doi:10.22059/ees.2022.254617

Motion dynamics of a water drop located on a hydrophobic inclined surface under uniform airflow

Authors

Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran

10.22059/ees.2022.254617

Abstract

Drop motion on a solid surface has many applications in science and engineering, such as in architecture, offshore structures, and electronics. The present paper aims to simulate the motion of a water droplet located on a hydrophobic inclined surface and investigate its deformation rate using ANSYS FLUENT software. The sessile droplet subjected to uniform airflow can be shed depending on the value of drag and drop’s adhesion forces. In the present work, coupled level set and volume of fluid method are employed to estimate the motion of the interface. The effect of drop size, wind velocity, drop contact angle, and drop size on the location, velocity, and drop deformation is investigated. The results demonstrate that the drop is splashed as the contact angle decreases. The drop acceleration has an approximately constant trend at Reynolds numbers ranging from 8000 to 80,000. The maximum acceleration corresponds to the hydrophilic surface and is equal to 0.9 m/s². As the contact angle increases, the acceleration becomes constant. For instance, the drop acceleration is about -0.3 for a contact angle of 135°. The results reveal that the drop requires a longer time to reach the lowest point of the inclined surface by decreasing its diameter and increasing surface hydrophobicity and wind velocity. It is found that as surface hydrophobicity increases, the drop reaches the bottom of the surface in a long time in comparison with the deformed drop.

Keywords

References

[1] Bayareh M, Mortazavi S (2011) Effect of density ratio on the hydrodynamic interaction between two drops in simple shear flow, Iranian Journal of Science and Technology, 35: 121-132.

[2] Bayareh M, Mortazavi S (2009) Numerical simulation of the motion of a single drop in a shear flow at finite Reynolds numbers, Iranian Journal of Science and Technology, 33: 441-452.

[3] Mohammadi Masiri S, Bayareh M, Ahmadi Nadooshan A (2019) Pairwise interaction of drops in shear-thinning inelastic fluids, Korea-Australia Rheology Journal 31(1): 25-34.

[4] Armandoost P, Bayareh M, Ahmadi Nadooshan A (2018) Study of the motion of a spheroidal drop in a linear shear flow. Journal of Mechanical Science and Technology. 32: 2059-2067.

[5] Bayareh M, Dabiri S, Ardekani AM (2016) Interaction between two drops ascending in a linearly stratified fluid, European Journal of Mechanics-B/Fluids, 60: 127-136. http://dx.doi.org/10.1016/j.euromechflu.2016.07.002

[6] Segre G, Silberberg A (1962) Behaviour of macroscopic rigid spheres in Poiseuille flow Part1. Determination of local concentration by statistical analysis of particle passages through crossed light beams. Journal of Fluid Mechanics. 14: 115-135.

[7] Griggs A J, Zinchenko AZ, Davis R. H (2008) Gravity-driven motion of a deformable drop or bubble near an inclined plane at low Reynolds number. International Journal of Multiphase Flow. 34: 408-418.

[8] Sakai M, Song JH, Yoshida N, Suzuki S, Kameshima Y, Nakajima A (2006) Direct observation of internal fluidity in a water droplet during sliding on hydrophobic surfaces. Langmuir. 22: 4906-4909.

[9] Dussan EB, (1988) On the ability of drops to stick to surfaces of solids. 3. The influences of the motion of the surrounding fluid on dislodging drops. J. Fluid Mech. 174: 381-397.

[10] Durbin A (1988) On the wind force needed to dislodge a drop adhered to a surface. Journal of Fluid Mechanics. 196: 205-222.

[11] Kumbur EC, Sharp KV, Mench MM (2006) Liquid droplet behavior and instability in a polymer electrolyte fuel cell flow channel. Journal of Power Sources. 161: 333-345.

[12] Vafaei S, Podowski MZ (2005) Analysis of the relationship between liquid droplet size and contact angle. Advances in Colloid and Interface Science. 113: 133-146.

[13] Hashimoto A, Sakai M, Song H, Yoshida N, Suzuki S, Kameshima Y, Nakajima A (2008) Direct observation of water droplet motion on a hydrophobic self-assembled monolayer surface under airflow. Journal of The Surface Finishing Society of Japan. 59: 907-919.

[14] Mortazavi S, Tafreshi MM (2013) On the behavior of suspension of drops on an inclined surface. Physica A: Statistical Mechanics and its Applications. 392: 58-71.

[15] Jin Z, Zhang H, Yang Z (2016) The impact and freezing processes of a water droplet on a cold surface with different inclined angles. International Journal of Heat and Mass Transfer, 103: 886–893. doi:10.1016/j.ijheatmasstransfer.2016.08.012

[16] LeClear S, LeClear J, Abhijeet Park K-C, Choi W (2016) Drop impact on inclined superhydrophobic surfaces. Journal of Colloid and Interface Science, 461: 114–121. doi:10.1016/j.jcis.2015.09.026

[17] Tembely M, Attarzadeh R, Dolatabadi A (2018) On the numerical modeling of supercooled micro-droplet impact and freezing on superhydrophobic surfaces. International Journal of Heat and Mass Transfer, 127: 193–202. doi:10.1016/j.ijheatmasstransfer.2018.06.104

[18] Xie J, Xu J, Shang W, Zhang K (2018) Mode selection between sliding and rolling for droplet on inclined surface: Effect of surface wettability. International Journal of Heat and Mass Transfer, 122: 45–58. doi:10.1016/j.ijheatmasstransfer.2018.01.098

[19] Han Y, He L, Wang S, Luo X, Zhou R (2020) Oscillation behaviors of oil droplets adhered on the solid surfaces with different wettability in a laminar flow field. Experimental Thermal and Fluid Science, 110057. doi:10.1016/j.expthermflusci.2020.110057

[20] Harges E, Cremaschi L, Adanur B (2021) Distribution, coalescence, and freezing characteristics of water droplets on surfaces with different wettabilities under subfreezing convective flow, Applied Thermal Engineering, 182: 116052. https://doi.org/10.1016/j.applthermaleng.2020.116052

[21] Roisman I V, Criscione A, Tropea C, Mandal D K, Amirfazli A (2015) Dislodging a sessile drop by a high-Reynolds-number shear flow at subfreezing temperatures. Physical Review E, 92(2). doi:10.1103/physreve.92.023007

[22] Carroll B, Hidrovo C (2013) Droplet Detachment Mechanism in a High-Speed Gaseous Microflow. Journal of Fluids Engineering, 135(7): 071206. doi:10.1115/1.4024057

[23] Moghtadernejad S, Jadidi M, Esmail N, Dolatabadi A (2016) Shear-driven droplet coalescence and rivulet formation. Proc. Inst. Mech. Eng. C: J. Mech. Eng. Sci., 230: 793-803.

[24] Hooshanginejad A, Lee S (2017) Droplet depinning in a wake. Phys. Rev. Fluids., 2: 031601.

[25] Razzaghi A, Amirfazli A (2018) Shedding of a Pair of Sessile Droplets. International Journal of Multiphase Flow. doi:10.1016/j.ijmultiphaseflow.2018.08.011