Large droplet breakup in free fall

Large droplet break-up occurs in many industrial processes and biological systems but is rarely studied in experiments because of the multiple scales and complexity. Further, the phenomenon is made more complex by examining shear thinning fluids. Here, we seek to unravel this complex phenomenon by looking at very large droplet breakup of both Newtonian and non-Newtonian liquids with droplet sizes greater than 30mm. Our experimental setup consists of a free-falling high-speed camera-light system simultaneously with a proprietary large droplet maker. This allows us to analyze droplets in a gravitationally accelerating flow field. Image analysis techniques are used to analyze the breakup in this controlled environment. The breakup of large Newtonian droplets can vary from vibrational breakup at low speeds to bagging at critical speeds. However, large shear thinning droplets have different Ohnesorge numbers which result in sheared droplets and multimode breakup. We show the various breakup types and compare them to smaller droplet breakup studies.