The objective of the proposed research is to explore the possibility of developing and deploying the equivalent of an "invisibility cloak" to render floating wind energy harvesting turbines invisible to ocean surface waves. Invisibility cloaks, made of metamaterial, have identified as one of the top ten important discoveries in solid state physics, optics, and acoustics in the first decade of 21st century, but this is now being discussed in the context of fluid mechanics and water waves.
Intellectual Merit An invisibility cloak for an object at the water surface can be accomplished when the surface waves detour the object as if the object does not exist, i.e., when there is no diffraction. An important consequence of such a cloaking is that floating structures and objects in a cloaked region will be protected from powerful incoming surface waves. The proposed research will take first strides into this area in a fluid mechanics context by using a combined theoretical, computational, and experimental approach. The research is focused on the effect of buoyancy jump (typical of oceans and lakes), viscosity, inertia, diffusion, and non-uniformities of seabed topography on cloaking in both sharp and continuous stratified fluids.
Broader Impacts This research program can lead to designing new strategies to protect moving and stationary ocean objects (ships, submarines, offshore platforms such as wind turbines) from disruptive effects of oceanic waves. In this work, fundamental fluid mechanics will be used to augment this area of aquatic science and oceanography. The proposed research is potentially transformative in that this area of fluid mechanics has to date gone mostly unexplored. The grant will also provide partial support for training two graduate students. The participation of women and members of underrepresented groups will be facilitated through the Women's Engineering Program at University of California Berkeley and Notre Dame. The PIs will ensure the participation of undergraduates through the Undergraduate Research Opportunity Program at both Berkeley and Notre Dame.
