GALCIT Colloquium

Unmanned aerial and underwater vehicles operating in real-world conditions must navigate complex environments, requiring understanding of flow interactions across vastly different scales. This talk presents two complementary approaches to this challenge. We first examine tandem configurations of self-propelled flexible flappers in controlled conditions through direct numerical simulation, revealing how hydrodynamic interactions between bodies determine collective performance. By systematically analyzing vortex-wake interactions, we identify scaling laws and reduced-order models that capture the essential physics of flow-mediated coupling. In turbulent environments, by contrast, the complexity of flow-mediated interactions makes systematic analysis of all possible effects intractable. In these complex regimes, we must identify which flow features govern performance and which can be neglected. The second part of the talk addresses how to systematically identify these governing parameters. We employ an information-theoretic framework to discover optimal scaling laws directly from data in non-equilibrium turbulent boundary layers subjected to favorable and adverse pressure gradients, including separation. This data-driven methodology reveals the non-dimensional groups that capture the essential physics needed to predict average flow quantities in non-equilibrium flows.