10/8/2013 Meredith Staub
Written by Meredith Staub
The boundary layer of any flow is the portion of the flow that feels the effect of the surface it is flowing against. In the atmosphere, for example, the wind feels drag as it moves against the stationary ground. This drag stops having an effect on the wind flow at some higher point in the atmosphere, which defines the limit of the boundary layer. The study of these kinds of flows has very broad applications—Chamorro’s research focuses on renewable energy with an emphasis on wind and hydrokinetic energy, geophysical flows, complex turbulent boundary layer processes, flow-structure interaction, and the development of new instrumentation for characterization of atmospheric turbulence processes.
The boundary layer in the atmosphere is on the order of one kilometer thick. Large wind turbines, which average about 100 meters high, operate where the effects of boundary layer turbulence are large. Studying the complex interplay between the turbulence and turbines can help us to improve controls on turbines and help optimize them while taking environmental effects into account. Chamorro and his group, the Renewable Energy and Turbulent Environment Group (RE-TE-G), are studying how to reduce the undue stress exerted on turbines by turbulence in the boundary layer, so as to make them more efficient, and are also addressing environmental aspects, such as wind farms' effect on pollinators. As many wind turbines are installed on farmland, ensuring that they won’t adversely affect the pollination of the crops is crucial.
"Bees are critical for our crops, and we know that bees are affected by turbulence," Chamorro said. "To better understand how turbulence and its structure across scales modulate the behavior of the bees, we are setting the infrastructure to track individual bees with various cameras both in a standard environment and in a wind farm environment. Then we will study how their trajectories and behaviors change with the flow turbulence generated by a wind farm."
Besides applying the study of atmospheric boundary layer flow to wind farms, Chamorro is also developing robust and novel instrumentation to characterize inclement weather and cloud dynamics at high temporal and spatial resolutions.
Chamorro is also very interested in the area of hydrokinetic energy, another form of renewable energy. Like wind energy, which places turbines in areas of strong wind flow and extracts its kinetic energy, hydrokinetic energy places turbines in areas of water flow. This can be in rivers, tidal currents, or in oceans. But what is the best technology, and what would be the effects on the environment?
"Even if it is clean energy, we don’t know how it can alter the dynamics of the ecosystem and the topology of the surrounding area," Chamorro said. "Are the fish going to be killed? What about the nutrient distributions in the river bottom or ocean bottom? What are the effects of the enhanced mixing in the water? We don’t know yet, but these are very important questions besides the technological aspect of the problem."
This semester Chamorro is teaching a graduate course in Theoretical and Applied Mechanics: TAM 538, Turbulence. He is also advising a group of students in the senior design class ME 470 who are building a hydrokinetic device, and the independent study class ME 597, which focuses on mathematical analysis of vortex-induced vibration in complex setups.
Chamorro received his B.S. in civil engineering from the University of Chile, and his M.S. and Ph.D. from the University of Minnesota, where he then continued to work as a research associate in the St. Anthony Falls Laboratory. There he helped found the lab's renewable energy program.