Michael Mewhinney

NASA Ames Research Center, Moffett Field, CA (Phone: 650/604-3937, 650/604-9000)



For the first time ever, engineers at NASA’s Ames Research Center will begin testing a wind turbine this month in the world’s largest wind tunnel to learn how to design and operate the turbines more efficiently.

The three-week test of the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) “Unsteady Aerodynamics” research wind turbine is scheduled to begin April 17. Tests will be conducted in Ames’ 80-by-120-Foot Wind Tunnel. The wind tunnel is primarily used for determining low- and medium-speed aerodynamic characteristics of full-scale aircraft and rotorcraft (helicopters).

“Some of the problems encountered by wind turbines are very similar to those experienced by rotorcraft,” explained Bob Kufeld, NASA project director. “NREL and NASA are working together using our wind tunnel and helicopter computer models that predict rotorcraft characteristics and their research wind turbine model to learn as much as possible about rotating blade aerodynamics,” he said.

“If we can better understand the aerodynamics of rotating blades, then we can more accurately predict how the wind turbines will behave,” said Dave Simms, NREL project director. “Our organization conducts research to make wind turbines operate more efficiently, more cheaply and more effectively,” he added. “This research will help us learn how to build better turbines.”

The research wind turbine is designed to measure structural loads and aerodynamic responses of the rotating blade or wing. The research wind turbine is mainly constructed from steel, but has lightweight carbon-fiber blades that measure 33 feet (10 meters) in diameter. The system weighs about 15,000 pounds (6,800 kilograms). Wind turbines, such as those found on the Altamont Pass in the East Bay (east of the San Francisco Bay, CA), are used to generate electricity for commercial uses.

During the wind tunnel test, the turbine will be mounted on a 40-foot tall stand and operated at a constant speed with its rotor turned left or right at various angles and different wind velocities. The wind tunnel is capable of producing wind velocities up to 115 miles per hour. NREL engineers developed the test objectives to meet recommendations of an international science panel of wind-turbine aerodynamics experts.

The NREL research turbine has been field-tested in various configurations since 1989 at the Department of Energy’s National Wind Technology Center located near Boulder, CO. It has been operated in outdoor atmospheric turbulent wind conditions up to 70 mph, and has been exposed to winds above 145 mph with the rotor locked in position. Test data have shown that turbulent winds create complex operating environments for wind turbines.

According to Simms, testing in a controlled wind-tunnel environment will eliminate these factors, and produce valuable data that will enable researchers to better understand how the turbines operate at various angles and wind speeds. “We need data to improve and validate enhanced engineering models for designing and analyzing advanced wind-energy machines,” Simms said. “Hopefully, this test will provide that data.”