Experimental study on slippery droplet dynamics using optical correction method

• Published in: Journal of mechanical science and technology Vol. 32; no. 10; pp. 4731 - 4736
• Main Authors: Gim, Yeonghyeon, Jang, Dong Kyu, Choi, Sung Ho, Kang, Giho, Seong, Baekhoon, Byun, Doyoung, Sohn, Dong Kee, Ko, Han Seo
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Mechanical Engineers 01.10.2018; Springer Nature B.V; 대한기계학회
• Subjects: Animal behavior; Computer simulation; Control; Droplets; Dynamical Systems; Elliptic fitting; Engineering; Gravitation; Industrial and Production Engineering; Industrial applications; Mathematical analysis; Mechanical Engineering; Polymethyl methacrylate; Ray tracing; Velocity distribution; Vibration; 기계공학; Flow visualization; Droplet dynamics; Droplet slippery; Optical correction
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-018-0920-3

When a droplet is placed on an inclined plane, it can slide down the plane by gravitational force. This phenomenon can occur in many industrial applications such as surface coating and printing, as well as in evaluating the characteristics of a surface. The slippery droplet can be analyzed from the balance between the gravitational force and the sum of the capillary and resistance forces. Researchers have suggested various equations of force balance with several hypotheses. To increase the reliability of the force balance correlation, it is important to obtain an accurate inside velocity profile and the three-dimensional (3D) shape of a droplet. In this paper, an analysis system of the slippery droplet was developed which includes optical correction based on a ray tracing method for velocity field measurement and an ellipse fitting method for droplet shape reconstruction. These correction methods were verified by a numerical simulation and applied to a slippery droplet on an inclined plate coated with Poly methyl methacrylate (PMMA). The wall shear force calculated from the velocity field and that calculated from the force balance were in good agreement.