ARNOLD AIR FORCE BASE, TENN. --
In the same year the U.S. Air Force is celebrating its 70th anniversary, Hypervelocity Wind Tunnel 9 is celebrating a historic milestone of its own.
October marks the 20th anniversary of the Hypervelocity Wind Tunnel 9 as an Air Force facility.
Tunnel 9, an AEDC site located at White Oak, Maryland near Silver Spring, became operational in 1976. The facility provides aerodynamic simulation critical to the development of hypersonic systems, including critical altitude regimes associated with strategic missile systems and advanced defensive interceptor systems, and hypersonic vehicle technologies.
The facility supports testing for Air Force, Navy, Army, Missile Defense Agency and NASA programs, as well as advanced hypersonic technologies such as wave-rider-type vehicles, scramjet inlets and transatmospheric space planes.
“As we pass this 20-year milestone as an Air Force Test Facility, a few recollections come to mind,” said Tunnel 9 Site Director Dan Marren. “In the first decade as an AEDC facility, we were getting our balance as we strived to build our processes, adjust to a new manager, and exist without any local support. In the second decade, having put the basics in place, the Tunnel 9 team operating as a true CTF [Combined Test Force], made amazing strides in revolutionizing our product, offering several new capabilities, diagnostics and insights for our customers. The advances in capability matched with growth of our technical staff skills was impressive.”
In 1995, just two years before becoming an Air Force facility, the Base Realignment and Closure (BRAC) commission closed the Navy White Oak site and threatened to close Tunnel 9. However, through the efforts of many, Tunnel 9 was kept open and continues to provide renowned capabilities to test hypersonic weapons at speeds as high as 14 times the speed of sound and over a wide range of altitude conditions.
Tunnel 9 is the primary high Mach number and high Reynolds number facility for hypersonic ground testing and the validation of computational simulations for the Air Force and Department of Defense, or DOD. Advantages of Tunnel 9 over other facilities include its unique storage heater with pressures up to 1,900 standard atmosphere and temperatures up to 3,650 degrees Reynolds. Axisymmetric contoured nozzles for Mach 6, 7, 8, 10 and 14 operation are also available.
The facility is also unique worldwide in its ability to provide a high Mach number, flight-representative environment for seconds of run time on large-scale geometries.
Other hypervelocity facilities have run times of a few milliseconds, but the long test times available at Tunnel 9, typically on the order of 1 second up to 15 seconds, provide higher productivity by allowing for parametric variation such as an angle-of-attack sweep or flow survey during a single run.
The 5-foot diameter test cell accommodates large-scale heavily instrumented test articles.
This combination of operational range, long test times and a large test cell makes Tunnel 9 the highest Reynolds number, largest scale ground-test facility in the world, capable of simultaneously collecting continuous pitch-polar static force and moment, pressure and heat-transfer data during each run. Having the capability to test at flight-matched Reynolds numbers provides a significant risk reduction for the design and evaluation of hypersonic systems.
Tunnel 9 provides a useful and cost-effective environment for research and development test and evaluation as well as for investigating the complex physics associated with hypersonic science and technology.
Past testing includes aerodynamic, aerothermal, seeker window thermal-structural and aero-optic, shroud removal, hypersonic inlet, fundamental flow physics and computational fluid dynamics validation experiments.
“In our next decade, I can truly say it is our time,” Marren said. “On our horizon I already see increasing workload with some of the highest priority work in the DOD, helping hypersonic technologies reach acquisition. I also see recapitalizing our aging infrastructure in a way that guarantees that we can provide the war winning test capabilities required for this difficult challenge.
“Finally, I see the seeds of workforce skills development we put in place grow to where not only will we have the right capability and tools but an extremely insightful and curious workforce to knit it all together.”
Editorial note: Information for this article was gathered from the article, “White Oak reaches 10-year mark as AEDC facility,” from the Oct. 5, 2007, edition of High Mach and the “Hypervelocity Wind Tunnel 9” excerpt from the AEDC Test Facility Guide.