Numerical study of droplet impact on superhydrophobic vibrating surfaces with microstructures

Abstract

The dynamic behavior characteristics of droplet impact on superhydrophobic microstructured surfaces vibrating in the vertical direction are evaluated with Computational Fluid Dynamics combined with Volume of Fluid technique. The effects of wall vibration amplitude, vibration frequency, phase angle and droplet velocity on contact time and maximum penetration depth are investigated. Results demonstrate that the phase angle affects the relative movement between droplet and vibrating surface, which causes changes of contact time and maximum penetration depth. The increase of vibration amplitude leads to larger fluctuation ranges of contact time and maximum penetration depth, compared with that on stationary surface. Moreover, the contact time decreases to the minimum values under nonresonant frequencies f* = 0.8, 1.2 at 270°, and the maximum values of maximum penetration depth curves are reduced along with the increase of vibration frequency. Furthermore, the contact time of droplet at dimensionless velocity 0.8 is shortened obviously in comparison with the results on stationary wall, while the maximum penetration depth of droplet at dimensionless velocity 1.5 is decreased the most. Finally, the surface vibration under dimensionless amplitude 0.2, and dimensionless nonresonant frequencies 0.8, 1.2 is obtained to improve dynamic behavior characteristics of droplet impact on superhydrophobic vibrating microstructured surfaces.

Keywords

• Droplet impact
• Vibrating microstructured surface
• Dynamic behavior characteristics
• Computational Fluid Dynamics