Wind tunnels are machines in which objects are held stationary inside a tube, and air is blown around it to study the interaction between the object and the moving air. They are used to test the aerodynamic effects of aircraft, rockets, cars, and buildings. Different wind tunnels range in size from less than a foot across, to over 100 feet (30 m), and can have air that moves at speeds from a light breeze to hypersonic velocities.
The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laboratory. That agency was dissolved and its assets and personnel transferred to the newly created National Aeronautics and Space Administration (NASA) on October 1, 1958. NASA Ames is named in honor of Joseph Sweetman Ames, a physicist and one of the founding members of NACA. At last estimate NASA Ames had over US$3 billion in capital equipment, 2,300 research personnel and a US$860 million annual budget.
The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets and personnel were transferred to the newly created National Aeronautics and Space Administration (NASA). NACA is an initialism, i.e., pronounced as individual letters, rather than as a whole word.
Compressible flow is the branch of fluid mechanics that deals with flows having significant changes in fluid density. While all flows are compressible, flows are usually treated as being incompressible when the Mach number is smaller than 0.3. The study of compressible flow is relevant to high-speed aircraft, jet engines, rocket motors, high-speed entry into a planetary atmosphere, gas pipelines, commercial applications such as abrasive blasting, and many other fields.
Transonic flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound, typically between Mach 0.8 and 1.2.
The Langley Research Center, located in Hampton, Virginia near the Chesapeake Bay front of Langley Air Force Base, is the oldest of NASA's field centers. LaRC has focused primarily on aeronautical research but has also tested space hardware such as the Apollo Lunar Module. In addition, many of the earliest high-profile space missions were planned and designed on-site. Langley was also considered a potential site for NASA's Manned Spacecraft Center prior to the eventual selection of Houston, Texas.
Robert T. Jones,, was an American aerodynamicist and aeronautical engineer for NACA and later NASA. He was known at NASA as "one of the premier aeronautical engineers of the twentieth century".
An oblique wing is a variable geometry wing concept. On an aircraft so equipped, the wing is designed to rotate on center pivot, so that one tip is swept forward while the opposite tip is swept aft. By changing its sweep angle in this way, drag can be reduced at high speed without sacrificing low speed performance. This is a variation on the classic swing-wing design, intended to simplify construction and retain the center of gravity as the sweep angle is changed.
A hypersonic wind tunnel is designed to generate a hypersonic flow field in the working section, thus simulating the typical flow features of this flow regime - including compression shocks and pronounced boundary layer effects, entropy layer and viscous interaction zones and most importantly high total temperatures of the flow. The speed of these tunnels vary from Mach 5 to 15. The power requirement of a wind tunnel increases linearly with its cross section and flow density, but cubically with the test velocity required. Hence installation of a continuous, closed circuit wind tunnel remains a costly affair. The first continuous Mach 7-10 wind tunnel with 1x1 m test section was planned at Kochel am See, Germany during WW II and finally put into operation as 'Tunnel A' in the late 1950s at AEDC Tullahoma, TN, USA for an installed power of 57 MW. In view of these high facility demands, also intermittently operated experimental facilities like blow-down wind tunnels are designed and installed to simulate the hypersonic flow. A hypersonic wind tunnel comprises in flow direction the main components: heater/cooler arrangements, dryer, convergent/divergent nozzle, test section, second throat and diffuser. A blow-down wind tunnel has a low vacuum reservoir at the back end, while a continuously operated, closed circuit wind tunnel has a high power compressor installation instead. Since the temperature drops with the expanding flow, the air inside the test section has the chance of becoming liquefied. For that reason, preheating is particularly critical.
Ira H. Abbott was an American aerospace engineer. After graduating from MIT, Abbott started working for Langley Aeronautical Laboratory in 1929. He contributed significantly to the establishment of high-speed research programs and published numerous technical reports on aerodynamics. He eventually attained the post of assistant chief of research at Langley in 1945.
The University of Texas at Arlington Aerodynamics Research Center (ARC) is a facility located in the southeast portion of the campus operated under the Department of Mechanical and Aerospace Engineering. It was established in 1986 as part of an expansion of UTA's College of Engineering. The ARC contributes to the vision of UTA and the University of Texas System to transform the university into a full-fledged research institution. It showcases the aerodynamics research activities at UTA and, in its history, has established itself as a unique facility at a university level. The wind tunnels and equipment in the facility were mainly built by scouting for and upgrading decommissioned equipment from the government and industry. Currently, Masters and Ph.D. students perform research in the fields of high-speed gas dynamics, propulsion, and Computational fluid dynamics among other projects related to aerodynamics.
A Trisonic Wind Tunnel (TWT) is a wind tunnel so named because it is capable of testing in three speed regimes – subsonic, transonic, and supersonic. The earliest known trisonic wind tunnel was dated to 1950 and was located in El Segundo, California before it closed in 2007. Other trisonic wind tunnels currently in operation are those located at NASA's Marshall Space Flight Center, National Researach Council Canada's 1.5 m Trisonic Wind Tunnel Research Facility and the French-German Research Institute of Saint-Louis, ISRO's Vikram Sarabhai Space Centre(VSSC) in Thiruvananthapuram, India.
Theodore Theodorsen was a Norwegian-American theoretical aerodynamicist noted for his work at NACA and for his contributions to the study of turbulence.
Clarence A. "Sy" Syvertson (1926-2010) was the Center Director of the Ames Research Center of the National Aeronautics and Space Administration, located at Moffett Field, California.
The Eight-Foot High Speed Tunnel, also known as Eight-Foot Transonic Tunnel, was a wind tunnel located in Building 641 of NASA's Langley Research Center in Hampton, Virginia. It was a National Historic Landmark.
The Variable Density Tunnel (VDT) was the second wind tunnel at the National Advisory Committee for Aeronautics (NACA) Langley Research Center. Proposed by German aerospace engineer, Max Munk, student of Ludwig Prandtl, it was the world's first variable density wind tunnel and allowed for more accurate testing of small-scale models than could be obtained with atmospheric wind tunnels.
As the coalition of Bay Areas counties predicted when it lobbied for the creation of Moffett Federal Airfield in the late 1920s, the base's research program and facilities catalyzed the development of numerous private technology and aerospace corporations, among them Lockheed Martin and the Hiller Aircraft Corporation.
The von Karman Gas Dynamics Facility at Arnold Engineering Development Complex, Arnold Air Force Base, Tennessee, provide aerothermal ground test simulations of hypersonic flight over a wide range of velocities and pressure altitudes. The facility consists of three Hypersonic wind tunnels: Tunnel A, B, and C. The wind tunnels can be run for several hours at a time thanks to a 92,500 horsepower air compressor plant system. The test unit is owned by the United States Air Force and operated by National Aerospace Solutions.
The Propulsion Wind Tunnel Facility, located at Arnold Engineering Development Complex, Arnold Air Force Base, Tennessee, holds three wind tunnels: the 16-foot transonic (16T), 16-foot supersonic (16S), and the aerodynamic 4-foot transonic (4T) tunnels. The facility is devoted to aerodynamic and propulsion integration testing of large-scale aircraft models. The tunnels are powered by a large compressor plant which allows the wind tunnels to run for extended periods of time. The test unit is owned by the United States Air Force and operated by Aerospace Testing Alliance.
