By William Calli ’24
In the relentless pursuit of sustainable energy sources, scientists and engineers have often turned their gaze toward the ocean for inspiration. One such naturally occurring process that has captured the imagination of researchers is vortex-induced vibration (VIV), a mesmerizing dance of fluid dynamics that occurs when a fluid flows past a cylindrical or streamlined structure, generating alternating vortices and causing the structure to oscillate.
In recent years, a series of Webb theses have explored utilizing this captivating natural occurrence for a noble cause: energy generation. The concept is elegantly simple yet profoundly effective. By placing structures engineered to exploit VIV in bodies of moving water, such as oceans or rivers, we can convert the kinetic energy of flowing water into electrical power.
Turning Flow into Power: Harnessing VortexInduced Vibrations with a Flutter-Foil.
The essence of VIV energy generation lies in its ability to capitalize on the Von Karman Vortex Street, a naturally occurring fluid-structure interaction. As water flows past a strategically positioned array of cylinders or flexible structures, the alternating vortices induce oscillations, which can be converted into electrical energy using various mechanisms such as piezoelectric materials, electromagnetic generators, scotch yokes, or in the case of this year’s thesis being carried out by Calli and Sanchez ’24, a rack and pinion.
The beauty of VIV-based systems lies not only in their potential to generate clean energy but also in their adaptability to diverse marine environments. Whether deployed deep below the tumultuous waves of the open ocean or immersed in the steady currents of a river, these systems can gracefully dance to the rhythm of nature, tirelessly generating power without emitting harmful greenhouse gases or depleting finite resources.
Enter the Marine Energy Collegiate Competition, a competition hosted by the National Renewable Energy Laboratory. For the third year in a row, this prestigious competition has invited Webb to compete among teams of students from around the country to design, build, test, and create a business case for their own marine energy devices. Webb’s entry into this competition is sure to stand out with an excellent technical design for a full-scale device, a business case centered around lowering the cost of energy for rural Alaskans, and model testing conducted as part of Calli and Sanchez’s thesis in Webb’s circulating water channel.
In the grand tapestry of our quest for sustainability, Webb thesis work on VIV-based energy generation stands as a testament to the ingenuity of Webb students and the powerful lessons to be learned from nature.