Liquid droplet impact on a sonically excited thin membrane

Area of Science:

• Fluid Dynamics
• Surface Science
• Acoustics

Background:

• Droplet impact on surfaces is crucial in various applications.
• Hydrophobic surfaces exhibit unique droplet interaction properties.
• Surface oscillations can modify these interactions.

Purpose of the Study:

• To investigate the effect of surface oscillations on water droplet impact.
• To analyze droplet behavior at different sonic excitation frequencies.
• To correlate membrane dynamics with droplet characteristics.

Main Methods:

• Utilizing high-speed imaging to capture droplet-surface interactions.
• Analyzing droplet contact duration, spreading, and rebound.
• Formulating restitution coefficient and membrane dynamics.
• Comparing experimental findings with theoretical models.

Main Results:

• Membrane oscillation modes vary with excitation frequency.
• At 75 Hz, droplet spreading and retraction decrease; rebound height and restitution coefficient increase.
• Higher frequencies decrease rebound height due to increased energy dissipation.
• Droplet contact duration decreases with increasing excitation frequency.
• Higher Weber numbers increase contact duration, especially at low frequencies.

Conclusions:

• Surface oscillations offer a method to control droplet impact behavior.
• Optimizing excitation frequency is key to maximizing rebound.
• Energy dissipation becomes a significant factor at higher frequencies.