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Droplet breakup against an isolated obstacle
David J Meer1, Shivnag Sista2, Mark D Shattuck3
1Department of Physics, Emory University, Atlanta, GA 30322, USA. dmeer@emory.edu.
Soft Matter
|March 16, 2026
Summary
This study reveals droplet breakup dynamics in microfluidics. Droplet breakup probability increases with flow velocity, size, and collision symmetry, predictable by a new breakup number (Bk).
Area of Science:
- Fluid Dynamics
- Microfluidics
- Particle Physics
Background:
- Understanding droplet behavior in microfluidic devices is crucial for various applications.
- Flow-driven interactions with obstacles can lead to droplet breakup or passage.
Purpose of the Study:
- To investigate the factors influencing single droplet breakup during flow-driven interactions with a circular obstacle.
- To develop a predictive model for droplet breakup likelihood.
Main Methods:
- Combined experimental and simulation approaches.
- Utilized quasi-two-dimensional microfluidic chambers.
- Employed discrete element method (DEM) simulations with a deformable particle model.
Main Results:
- Droplet breakup is favored by higher flow velocity, larger droplet size, lower surface tension, and head-on collisions.
- Increased chamber height enhances the likelihood of droplet-obstacle collision breakup.
- A nondimensional breakup number (Bk ~ Capillary number) was defined, predicting a transition from no breakup (Bk << 1) to consistent breakup (Bk >> 1).
- Bk correlates with collision symmetry (S), indicating a minimum symmetry threshold for breakup.
Conclusions:
- Droplet breakup in microfluidic flow is governed by a combination of fluid properties, geometry, and collision dynamics.
- The developed breakup number (Bk) provides a quantitative measure to predict droplet breakup events.
- Collision symmetry plays a critical role in determining the minimum conditions required for droplet breakup.
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