Research Projects

The proposed research aims to fill knowledge gaps in understanding the behavior of non-Newtonian fluids, particularly in the context of sheet breakup. Newtonian fluids have been extensively studied, but non-Newtonian fluids, particularly liquid sheets, remain unexplored. It is unclear how rheology, particularly shear-thinning and viscoelastic properties, plays a role in sheet atomization. The project proposes controlled experiments on the atomization of non-Newtonian fluid sheets, focusing on sheet oscillations, rim oscillations, impingement point dynamics, ligament dynamics, and final droplet distribution and kinematics. High-speed shadowgraphy, low-speed PLIF, and long-distance microscopy will be used as primary diagnostics. Comprehensive physical and rheological characterization of test fluids will be performed to correlate observed sheet dynamics with rheology. Data analysis will be based on methodologies from various experiments. The project is significant because there are significant knowledge gaps in the field, particularly in the correlation between rheological properties and sheet dynamics. The primary focus is on the development of hydrodynamic waves, instability of a liquid rim, formation and evolution of perforations in the free liquid sheet, unsteady fragmentation of the sheet due to waves and perforations, formation and evolution of ligaments and droplets, and the breakup of ligaments into droplets. Each of these aspects is relevant to the final droplet size distribution and is expected to be influenced by fluid rheology in a way that cannot be described with just a single apparent viscosity at the jet exit.