Collaborative research: propulsion in the middle ground: using animal models to evaluate propulsion hydrodynamics at lower intermediate reynolds numbers

The National Science Foundation Division of Chemical, Bioengineering, Environmental, and Transport Systems awarded Providence College $199,132 on July 15, 2026, to investigate propulsion hydrodynamics in small animals swimming at intermediate Reynolds numbers and to develop engineering applications informed by these findings.

The research will combine high-speed imaging with measurements of fluid velocity, pressure, and energetic cost to quantify interactions between moving animal bodies and surrounding fluids. The investigators will study representative organisms employing three major propulsion forms—jetting, body undulation, and coordinated paddling—and integrate experimental measurements with computational fluid simulations to identify fluid-structure interactions responsible for enhanced performance. This work addresses the physical mechanisms allowing small animals to achieve high transport efficiency in flow regimes where neither fluid inertia nor viscosity dominates, with implications for the design of small pumps, medical devices, and underwater robotic vehicles. The project will also develop educational materials for K–12 classrooms and provide interdisciplinary research experiences for undergraduate and graduate students through partnerships with marine science organizations.

Performance occurs at Providence College in Providence, Rhode Island, with a period of performance through June 30, 2029. This is a project grant under NSF Engineering (CFDA 47.041).

Abstract

Engineering models suggest that small animals face a difficult physical challenge when they move through water. Models predict that fluid transport is surprisingly inefficient on the scale of small animals. Yet many small animals routinely outperform these predictions, swimming faster and moving water more effectively than expected. Understanding how these animals accomplish this feat is important because similar constraints limit the performance of small pumps, medical devices, and underwater vehicles. This project will investigate how animals have repeatedly solved this problem throughout evolutionary history and determine whether those solutions can inspire improved engineering designs. The project will also provide interdisciplinary research experiences for undergraduate and graduate students, develop educational materials for k?12 classrooms, and engage the public through partnerships with marine science organizations and outreach programs. Project outcomes will support manufacturing and use of robotic vehicles and innovations in biomedical device design. This project will determine the physical mechanisms that allow animals to achieve high transport efficiency in a flow regime where neither fluid inertia nor viscosity dominates. The investigators will study representative organisms that use three major forms of propulsion: jetting, body undulation, and coordinated paddling. High-speed imaging will be combined with measurements of fluid velocity, pressure, and energetic cost to quantify the interactions between moving bodies and surrounding fluids. The experimental measurements will be integrated with computational fluid simulations to identify the fluid-structure interactions responsible for enhanced performance. The resulting datasets will be used to develop predictive relationships linking body motion, flow conditions, energy expenditure, and transport efficiency across a critical range of flow environments. The research will advance fundamental understanding of fluid mechanics and biomechanics while providing design principles relevant to small-scale propulsion and pumping technologies. The project will support interdisciplinary workforce development, participation of undergraduate researchers in cutting-edge science, creation of inquiry-based educational materials for k?12 audiences, and dissemination of discoveries through public outreach and marine science education programs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.