20 December 2007

Wind turbines produce airflow mysteries

Researchers are looking more closely at the dynamics of wind turbines, and they will develop computer models to improve their performance.

Using smoke, laser light, model airplane propellers, and a campus wind tunnel, a team at Johns Hopkins University is trying to solve the airflow mysteries that surround wind turbines, an increasingly popular source of "green" energy.

The National Science Foundation recently awarded the team a three-year, $321,000 grant to support the project.

The rise in oil prices and a growing demand for energy from non-polluting sources has led to a global boom in construction of tall wind turbines that convert the power of moving air into electricity.

Wind turbine at Johns Hopkins University
A wind tunnel at Johns Hopkins University

The technology of these devices has improved dramatically in recent years, making wind energy more attractive. For example, Denmark is able to produce about 20% of its electric energy through wind turbines.

However, important questions remain:

  • Could large wind farms, whipping up the air with massive whirling blades, alter local weather conditions?
  • Could changing the arrangement of these turbines lead to even more efficient power production?

The researchers from Johns Hopkins and Rensselaer Polytechnic Institute hope their work will help answer such questions.

"With diameters spanning up to 100 meters across, these wind turbines are the largest rotating machines ever built," said research team leader Charles Meneveau, a turbulence expert in Johns Hopkins' Whiting School of Engineering.

"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. 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."