Numerical study on dynamic characteristics of double droplets impacting a super-hydrophobic tube with different impact velocities

ABSTRACT

The coupled level set and volume of fluid method is applied to the numerical study on the successive impact of double droplets on a super-hydrophobic tube. The impact velocity varies from 0.25 to 2 m/s. These impact processes present spread, retract, rebound, breakup and splash. The out-of-phase impact takes place with the impact velocity from 0.25 to 1.25 m/s, while the in-phase impact takes place with the impact velocity from 1.44 to 2 m/s. With the impact velocity larger than 1.25 m/s, the liquid crown presents and deforms after the trailing droplet impact, then it would gather at the film edge, rebound or break up. When impact velocities range from 1.44 to 1.5 m/s, the finger liquid film presents before the liquid crown appearing. The finger head breaks with the impact velocity of 1.5 m/s during the leading droplet spreading. The zigzag liquid film becomes more obvious for larger velocities.

KEYWORDS:

• Double droplets
• super-hydrophobic tube
• out-of-phase impact
• in-phase impact
• impact velocity

Additional information

Funding

This work is supported by the National Natural Science Foundation of China (No. 51476017) and the National Natural Science Foundation of China (No. 51576029).