The focus of this CAREER project is to use concepts from passive/active flow control from the field of aerodynamics in order to control flow-surface interactions at the geophysical scale. The large characteristic scales of natural landscapes are found to overlap with the very large scale structures of the turbulent flow that continuously reshape the confining landscape (such as flow of rivers, ocean streams, or wind). The PI proposes to explore the relationship between the large scales of turbulent flows and the evolution of an erodible topography, and then to use this knowledge along with flow control concepts to shape natural topography, introducing the concept of Geophysical Flow Control (GFC). Intellectual Merit: Flow control has been extensively used in aeronautics to control laminar to turbulent flow transition on airfoils, or to alter the structure of turbulent boundary layers through perturbations of the boundary conditions. In many geophysical flows, the observed large scale patterns result from flow instabilities somewhat different from those governing turbulent wall-bounded flows. The PI proposes to extend the flow control approach to the case of meandering flows in natural or built environments, aiming at achieving specific flow or topographic patterns. By identifying the intrinsic instabilities of a natural dynamical system and by understanding their governing mechanism one can selectively dampen these instabilities and control their effects. Geophysical flow control will be validated through specific benchmark experiments.
Broader Impacts:
Successful completion of the project will enable the control of the formation and evolution of meandering patterns affecting the economy of entire communities in coastal or fluvial environments. Fundamental knowledge generated through this project can affect river and estuarine restoration projects, as well as the process of harnessing energy in river flows with the deployment of marine hydrokinetic turbines at the appropriate locations. The educational plan is to construct a movable GFC demonstration model that can be used, for example, at the Minnesota Stare Fair or in K-12 tours. It also includes the establishment of an open competition for a remotely-controlled experiment and a virtual field experiment. The ongoing outreach activities at St. Anthony Falls Laboratory at the University of Minnesota will be utilized to bring exposure of the educational activities of the project to students and the public.
