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

RELEASE: 00-54

NASA TO TEST WIND TURBINE IN WORLD'S LARGEST WIND TUNNEL

     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."

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