This talk will cover two research topics (bubbles and droplets), which are initiated by looking at daily life through the lens of curiosity. i) A common lab 'disaster' is when a test tube filled with chemical solution drops on the floor. The test tube cracks and the liquid in it spills and splashes. But what happens there? The actual physical process of this failure is a bit counterintuitive. It is not the moderate impact itself that breaks the glass. Instead, the impact-induced high acceleration causes the cavitation bubble(s) to grow and collapse in the liquid, which cracks the glass. ii) Why a dog lifts one of its hind legs when peeing against a tree or wall? We found that this is a smart practice because it can reduce urine splashback. Inspired by dogs, and nautilus shells, we designed splash-free urinals for humans by embedding the physics of droplet impact, solving differential equations, and carefully considering accessibility for people of different length scales. Last, we will introduce some of our on-going experiments, which are open to mathematical explanations.

Short Bio:

Zhao Pan is an Assistant Professor in the Department of Mechanical and Mechatronics Engineering at the University of Waterloo and the Principal Investigator of the Interdisciplinary Fluid Physics Lab - Pan Lab. Prior to joining Waterloo, he worked at Utah State University and Florida Center for Advanced Aero-propulsion (FCAAP, FSU) as a postdoctoral fellow. His research interests span from fundamental fluid physics (e.g., jets, bubbles, droplets, and cavitation), micro/bio-fluids, to advanced fluid flow diagnostics. Most of his studies are driven by curiosity and serve both academia and the community with creative ideas and broader social impact. Working with scientists and engineers from different fields, his multi-disciplinary fluid dynamics studies have been published in journals such as PNAS, Nature Plants, J. Fluid Mech, Phys. Rev. Fluids, Phys. Fluids, and Soft Matter, etc. His works have been featured on journal covers (Nature, Plants, Soft Matter), editor’s picks, and in 40+ leading media outlets (e.g., Science, Nature, The Washington Post, EurekAlert!, etc.).