A team led by Johns Hopkins University researchers is trying to solve airflow mysteries that surround wind turbines. The National Science Foundation recently awarded the team a three-year, $321,000 grant to support the project.
The group is trying to determine whether large wind farms alter local weather conditions and if the arrangement of wind turbines leads to more efficient power production.
‘There's been a lot of research done on wind turbine blade aerodynamics, but few people have looked at the way these machines interact with the turbulent wind conditions around them,’ says Charles Meneveau, a turbulence expert in Johns Hopkins' Whiting School of Engineering. ‘By studying the airflow around small, scale-model windmills in the lab, we can develop computer models that tell us more about what's happening in the atmosphere at full-size wind farms.’
To collect data for such models, Meneveau's team is conducting experiments in a campus wind tunnel. The tunnel uses a large fan to generate a stream of air moving at about 40 mph. Before it enters the testing area, the air passes through an ‘active grid,’ a curtain of perforated plates that rotate randomly and create turbulence so that air currents in the tunnel more closely resemble real-life wind conditions. The air currents then pass through a series of small model airplane propellers mounted atop posts, mimicking an array of full-size wind turbines.
‘What happens when you put these wind turbines too close together or too far apart? What if you align them staggered or in parallel?’ asks Raul B. Cal, a Johns Hopkins postdoctoral fellow working on the project. ‘All of these are different effects that we want to be able to comprehend and quantify, rather than just go out there and build these massive structures, implementing them and not knowing what's going to happen.’