Zhao Pan

Zhao Pan is a Chinese mechanical engineer. He is a fluid dynamics researcher and assistant professor in the Department of Mechanical and Mechatronics Engineering at the University of Waterloo in Ontario, Canada. He is the principal investigator of the university's interdisciplinary Fluid Physics Laboratory, also known as the Pan Lab.

Education and career

Pan received a master's degree in automotive engineering from Jilin University and a master's degree in mechanical engineering from the University of Louisiana at Lafayette. He earned a doctorate in mechanical engineering from Brigham Young University in 2016. Before joining the University of Waterloo, Pan worked as a postdoctoral researcher at the Florida Center for Advanced Aero-Propulsion and Utah State University. He joined the University of Waterloo in late 2019.

Research

Pan's research concerns fluid dynamics and related areas, including biomechanics, microfluidics, biofluidics, flow diagnostics, uncertainty quantification, velocimetry-based pressure measurement, cavitation, droplets, bubbles, jets, and dynamics and control. The Pan Lab describes its work as combining fundamental fluid physics with experimental measurement and mathematical modelling. His research includes experimental and computational studies of rapidly changing fluid phenomena. The methods used in this area include particle-image velocimetry, pressure-field calculations, data assimilation, and mathematical modelling of fluid motion.

In 2016, Pan worked as the main author of a study investigating the ability of the desert moss Syntrichia caninervis to collect water through hair-like structures found at the edges of its leaves. The study revealed that the moss features microscopic grooves and barbs that allow it to collect humidity from fog and vapor and move the droplets toward the leaves.

Pan also have studied cavitation. He understood the mechanism of formation and subsequent collapse of vapor bubbles in liquids. He collaborated with some researchers of Tsinghua University.

Pan made a research on splash-free urinals in 2022 and it was covered by Ars Technica, and in 2026 he received the Ig Nobel Prize in Physics for this work.

Splash-free urinals

In 2025 Pan was the corresponding author of the research article "Splash-free Urinals for global sustainability and accessibility: Design through physics and differential equations", published in PNAS Nexus. The article was co-authored by Kaveeshan Thurairajah, Xianyu Song, J. D. Zhu, Mia Shi, Ethan A. Barlow, and Randy C. Hurd. The study examined the relationship between the angle at which a liquid stream strikes a surface and the resulting splash. The authors reported that splashback was substantially reduced when the impinging angle was 30 degrees or less. On the basis of this principle, the researchers designed two urinals called Cornucopia and Nautilus. In experiments, the designs produced approximately 1.4 percent of the splash measured for a contemporary commercial urinal. The paper also estimated that the Nautilus design could reduce water used for cleaning in some non-residential settings and improve accessibility through its shape and dimensions. The research was covered by Ars Technica, which described the designs as an attempt to reduce splashback by controlling the angle at which the stream meets the surface. Pan, Randy Hurd, Tadd Truscott, and Kaveeshan Thurairajah received the 2026 Ig Nobel Prize in Physics for "theoretical and experimental attempts to design a splash-free urinal".

Selected publications

• Pan, Zhao (2019). "The water entry of a sphere in a jet". Journal of Fluid Mechanics. 863: 956–968. Bibcode:2019JFM...863..956S. doi:10.1017/jfm.2018.931.
• Pan, Zhao (2018). "The water entry of multi-droplet streams and jets". Journal of Fluid Mechanics. 844: 1084–1111. Bibcode:2018JFM...844.1084S. doi:10.1017/jfm.2018.204.
• Pan, Zhao (2018). "Drop on a Bent Fibre". Soft Matter. 14 (19): 3724–3729. arXiv:1712.09015. Bibcode:2018SMat...14.3724P. doi:10.1039/C7SM01729D. PMID 29542766.
• Pan, Zhao (2017). "Cavitation onset caused by acceleration". Proceedings of the National Academy of Sciences. 114 (32): 8470–8474. Bibcode:2017PNAS..114.8470P. doi:10.1073/pnas.1702502114. PMC 5559011. PMID 28739956.
• Pan, Zhao (2016). "The upside-down water collection system of Syntrichia caninervis". Nature Plants. 2 (7) 16076. Bibcode:2016NatPl...216076P. doi:10.1038/nplants.2016.76. PMID 27302768.
• Pan, Zhao (2016). "Error propagation dynamics of PIV-based pressure field calculations: How well does the pressure Poisson solver perform inherently?". Measurement Science and Technology. 27 (8). arXiv:1602.00037. Bibcode:2016MeScT..27h4012P. doi:10.1088/0957-0233/27/8/084012. PMC 4972504. PMID 27499587.
• Pan, Zhao (2017). "Shear Joy of Watching Paint Dry". Physical Review Fluids. 2 (9) 090503. Bibcode:2017PhRvF...2i0503H. doi:10.1103/PhysRevFluids.2.090503.