Universal dripping and jetting in a transverse shear flow

Area of Science:

• Fluid dynamics
• Colloid and interface science
• Materials science

Background:

• Producing emulsions with uniform droplet sizes is crucial for various applications.
• Existing methods for emulsion generation can be complex or inefficient.
• Understanding droplet formation dynamics is key to controlling emulsion properties.

Purpose of the Study:

• To present an efficient method for generating monosized emulsion droplets.
• To develop a predictive model for droplet size based on fluid properties and flow conditions.
• To investigate the different flow regimes and nonlinear behaviors in droplet formation.

Main Methods:

• A fluid is injected through an orifice into a transverse flow of an immiscible fluid.
• Droplet size is analyzed using a force balance model at intermediate particle Reynolds numbers.
• System behavior is characterized by varying capillary, Weber, and Ohnesorge numbers.

Main Results:

• A simple force balance accurately predicts droplet size at intermediate particle Reynolds numbers.
• The system exhibits distinct dripping and jetting behaviors, analogous to a dripping faucet.
• Nonlinear phenomena, including period doubling, are observed near the transition between regimes.

Conclusions:

• The described method provides an efficient route to producing monosized emulsion droplets.
• The force balance model offers a practical tool for controlling droplet size in this system.
• The observed dripping-jetting transition and nonlinear dynamics offer insights into interfacial phenomena.