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NSF Grant Supports Chengyu Li’s Research on Flow Across Scales

Dr. Chengyu Li

Following his 2020 CAREER grant for “Odor-guided flapping flight: Novel fluid dynamic mechanisms of insect navigation,” the National Science Foundation has awarded Mechanical Engineering Assistant Professor Dr. Chengyu Li nearly $184,000 for “Scaling of ciliary flows at intermediate Reynolds number.” A better understanding of the fluid dynamics of cilia across scales will provide insights related to biology, ecology, and the fundamental physics of how flexible structures create flow across scales.

Cilia are flexible hair-like appendages commonly used to create fluid motion in biological systems, facilitating swimming, feeding, reproduction, and other functional behaviors. Typical cilia are tens of microns long, but ctenophores (comb jellies) use cilia at much larger scales—around a millimeter in length. At small scales, ciliary flow is highly constrained by fluid viscosity. However, at larger scales, inertia becomes more important, leading to quantitative and qualitative differences in the velocities and forces produced by the cilia.

Dr. Li will collaborate with Dr. Margaret Byron at Penn State University to explore these differences with a combination of laboratory experiments (Penn State) and computational simulations (Villanova), using ctenophores as a model system for large-scale cilia. This integrated approach will enable an in-depth investigation of how flexible structures generate flow across the viscous-inertial transition, and the development of broadly applicable scaling principles to guide future technology development including bioinspired devices, sensors, and robots.