The Glenn L. Martin Wind Tunnel
"What makes this special for me is the coupling between academia and the industrial world. I have a strong foot in both areas and find it suits me very well."
The Wind Tunnel fan chamber, front view of the fan. To get an idea of its scale,
see the "Fan-tastic" sidebar.
The Glenn L. Martin Wind Tunnel has been a cornerstone of the Department of Aerospace Engineering since 1949. One of fewer than a dozen low-speed wind tunnels in the nation, it has been consistently upgraded, remaining in regular service and maintaining its reputation as a state-of-the-art facility. As of 2005, it has hosted more than 1900 tests in aero- and hydrodynamics. Over the years, the Wind Tunnel has boosted the research and development capabilities of numerous local and national businesses, resulting in better products for consumers, the military, specialty markets, and research opportunities for Clark School students.
Ours is a subsonic, or low-speed, wind tunnel, which means it is capable of generating wind speeds up to 3/10ths the speed of sound—in our case, a maximum of 230 miles per hour. This makes it ideal for testing a wide variety of vehicles, aircraft, buildings, devices and the unexpected or unique, including the occasional daredevil meteorologist. Anything that has to contend with the wind could become a test subject.
Planes, Trains and Automobiles
Over the last 25 years, the wind tunnel has regularly been used to test automobile aerodynamics, including almost all of the Ford Motor Company's scale-model tests. In addition, the wind tunnel has hosted tests for planes, from ultralights to jet fighters to commercial airliners; and other airborne vehicles and devices including helicopters, missiles and parachutes. It has also seen its share of more unusual vehicles, including a hovercraft and the Pride of Maryland solar-powered car. (See the "Nascar Connections" sidebar for more information.)
When Wind Equals Water
How can a wind tunnel measure hydrodynamics? Because air and water behave in the same way below 3/10ths the speed of sound, it is possible to test parts of boats that are below the waterline, and objects that are completely submerged, including submarines. Since the 1980s, the Wind Tunnel has partnered with the renowned Annapolis-based Farr Yacht Design to improve keels on America's Cup and Volvo 60 class yachts. Working above the water line, the wind tunnel has helped take Quantum Sails (also of Annapolis) to world-class status.
The effectiveness of a sail is tested on a scale-model of an America's Cup yacht. The smoke shows the air flow in regions away from the surface.
Birds and Bobsleds
The U.S. Bobsled team gets ready for the 2004 Winter Olympics.
Sometimes, Wind Tunnel Director Jewel Barlow admits, people approach his staff with projects they could never have anticipated. The Smithsonian explored the evolution of flying squirrels, while the Patuxent Wildlife Center explored the effects of attaching tracking devices to birds. In preparation for the 2004 Olympics, the U.S. Bobsled Team used the Wind Tunnel to analyze how changes in the sled's design and its crew's positions would affect its time on the track.
Live from the Glenn L. Martin Wind Tunnel...
One novel request in 1988 lead to something now familiar to the public: a TV meteorologist contacted Dr. Barlow and asked if he could be strapped into the test area to demonstrate the force and speed of the winds Hurricane Gilbert was about to bring to the Gulf of Mexico. It went over so well that Dr. Barlow is contacted by multiple stations every time a hurricane threatens our shores, sometimes resulting in competing meteorologists trying to outdo each other by asking for higher and higher speeds! (The wind tunnel staff has always set a speed limit to avoid any injuries.) Members of the media interested in writing a story or filming a segment may contact the Glenn L. Martin Wind Tunnel to learn about scheduled Media Days.
The wind tunnel offers full-time, co-op positions for undergraduates interested in current aerodynamic research and development. It has also opened its doors to student projects. The Society of Automotive Engineers has tested its designs in the Wind Tunnel, and aerospace engineering holds a senior lab there. The Solar Decathlon team used it to determine the possibility of wind damage to the solar panels on its house.
In order to study air or water flow across objects' surfaces, colored oil is spread on scale models with a paint brush. The tunnel's wind speed is then brought up to a selected value. The oil moves according to the flow direction of the air at the surface of the model.