Numerical study on active droplet generation governed by pulsatile continuous‐phase flow

Precise control on the droplet generation is an important issue for the application of droplet microfluidics. Passive formation of droplets depends on multiparameters. The droplet size and generation frequency highly correlate to each other, raising the control difficulty. In comparison, the active method through external perturbations is more flexible. In this work, the droplet generation governed by pulsatile continuous‐phase flow is numerically studied. The effects of the pulsation amplitude and frequency, as well as the velocity and viscosity of the discrete fluid are investigated. Different modes of droplet generation (viz., sub‐periodic, period‐1, and period‐n modes) are identified, the underlying mechanisms are interpreted. This method may be applied in various droplet microfluidic/microreactor systems to improve the droplets control and manipulations.