SWARM · Direct measurements of collective swimming forces at the mesoscale

Swimming is ubiquitous in nature and crucial for the survival of a wide range of organisms. Many swimmers move together in intricate swarms, widely believed to save energy through collective hydrodynamic interactions. While the physics behind swimming and swarming of viscosity-dominated microswimmers and inertia-dominated macroswimmers has been extensively studied, little is known about the intermediate regime (~ 0.1–10 cm), where both viscous and inertial forces are important. This mesoscale is full of living organisms, such as small larvae, shrimps, and jellyfish, and the physics behind their swimming and swarming is strongly complicated by non-linear and time-dependent effects at increasing swimming speeds and organism sizes. A breakthrough in our understanding of mesoscale swarming dynamics is hindered by an absence of force-based experiments on collective mesoswimming. Here, I will perform pioneering experiments on the swimming forces of brine shrimps as model organisms. I aim to discover how they adapt their motility in different environments and perform the first direct measurements on the binary and many-body swimming and hydrodynamic interaction forces within pairs and small swarms of brine shrimps. I aim to resolve several major questions on mesoscale motility and swimming interactions, with the grand goal to discover new insights into how and why swarms of mesoswimmers are formed in nature. My experiments will open a new living matter physics research avenue at the mesoscale, and provide sensitive and important force and fluid dynamics data for theorists to use in their future models and for engineers to use in their biomimicry design of new mesorobots. The indirect impact of my work is the creation of new biomedical and engineering applications at the mesoscale, such as swallowable surgery with swarming mesorobots capable of optimising their swarm geometry to minimise power consumption in different environments.