Manipulating Shedding Vortices Guided by Harmonic Resolvent Analysis

Swirling flow patterns known as vortices arise whenever air or water moves past structures such as bridges, aircraft wings, buildings, and underwater vehicles. While these motions can sometimes be useful, for example by improving mixing or ventilation, they often create serious challenges. Vortices can increase drag on vehicles, generate loud noise, and cause damaging vibrations that shorten the lifespan of infrastructure. Being able to anticipate and precisely control these swirling motions would allow engineers to design safer bridges, more efficient airplanes, quieter communities, and more reliable energy and cooling systems. Today, however, strategies for controlling these flows rely heavily on trial-and-error testing because it is difficult to determine which small disturbances in the flow meaningfully affect vortex behavior. This project develops a physics-based method that identifies the disturbances most responsible for strengthening or weakening vortices, enabling more targeted and energy-efficient control approaches. The project also integrates research with education by creating virtual-reality learning tools that let students explore complex airflow patterns in an immersive environment. These tools will enhance undergraduate and graduate instruction at Syracuse University and will be shared with local K–12 students through community partnerships, helping inspire students to pursue careers in science and engineering. This project supports new understanding for advanced manufacturing of many kinds of vehicles. This project advances a computational framework called Harmonic Resolvent Analysis to investigate how flow disturbances develop, interact, and exchange energy within unsteady, vortex-dominated flows. Unlike existing methods, which assume the background flow is steady, this new approach incorporates time-varying base states, allowing it to capture cross-frequency interactions and multi-scale disturbance dynamics that strongly influence vortex formation. The research includes three thrusts: (1) conducting high-fidelity simulations of flows with free and wall-bounded vortex shedding under both steady and unsteady incoming conditions; (2) applying the enhanced analysis framework to identify the dominant physical mechanisms that govern vortex growth, three-dimensional instabilities, and energy transfer across frequencies; and (3) using these insights to design and evaluate three-dimensional fluidic actuation strategies capable of suppressing or amplifying vortex strength using minimal energy input. The project will validate theoretical predictions against detailed simulations and establish guidelines for translating linear disturbance analysis into practical control designs. Educational outcomes include incorporating research findings into new and existing courses and creating virtual-reality content for classrooms and outreach programs, supporting the development of next generation of engineers and scientists. 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.