AEDC's Hypervelocity Wind Tunnel 9 reaches 3,000-run milestone

Rita Bell, Tunnel 9 employee, “pushes the button” for the 3000th run at Tunnel 9. Bell was present during the facility’s first run in 1976.

Rita Bell, Tunnel 9 employee, “pushes the button” for the 3000th run at Tunnel 9. Bell was present during the facility’s first run in 1976.

ARNOLD AIR FORCE BASE, TENN -- March 15 marked an important milestone for one of Arnold Engineering Development Center's (AEDC) world-unique test assets. The Hypervelocity Wind Tunnel 9, located at AEDC's White Oak near Silver Spring, Md., completed its 3,000 test run as the facility approaches 30 years of operation. The first test, ironically in support of an Air Force system, occurred in 1976 when the facility was operated by the U.S. Navy as part of the (then) White Oak site of the Naval Ordnance Laboratory.
In its early years of operation, Tunnel 9 completed an average of 100 runs per year, with a record of 281 runs in 1985. But technology advancements in more recent years have enabled the team to test more proficiently with fewer runs, saving customers time and money and providing better data than ever before.
"Today, through the use of powerful computational methods, far fewer, yet highly accurate and more complex, test runs are needed to validate computational fluid dynamics codes," AEDC White Oak Site Director Dan Marren said. "With today's more efficient operations, Tunnel 9's expert staff can support about 60-80 runs per year, focusing on unique physics-based challenges. This year, Tunnel 9 is running at near maximum capacity for the U.S. Air Force, DARPA, NASA, U.S. Navy and the Missile Defense Agency, and fiscal year 2007 is looking just as productive."
A typical test in Tunnel 9 acquires about one to two seconds of data. "In a single second, Tunnel 9 can obtain surface pressures, heat transfer data and characterize the forces acting on a test article while simultaneously changing the model's altitude," Marren
said. Other facilities attempting to replicate this extreme test environment operate for 1/1,000 of a second making Tunnel 9 unique in its ability to obtain design information.
During tests in Tunnel 9, the Missile Defense Agency's Theater High Altitude Area Defense (THAAD) interceptor program proved out its flight characteristics, protective heat shield design, divert and attitude control jets, seeker window and shroud separation. The total test time to understand these systems, which later proved successful in flight with help from Tunnel 9 data, was less than five air-on minutes.
Thirty years of testing has produced approximately one hour of data when all of the test runs are added together. Tunnel 9 has been, and continues to be, critical in the development of accurate strategic reentry systems; in aiding successful earth reentry for NASA's space shuttle; in enabling direct hit missile defense interceptors at closing speeds approaching 10,000 mph; and in advancing our understanding of complex aerodynamics and aerothermodynamic phenomenon of high-speed propulsion systems. "When you are used to continuous wind tunnels operating at less severe environments, you tend to think that one air-on hour is short," Marren said. "But consider what system advances Tunnel 9 has enabled in a single hour."