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Sting (fixture)
In experimental fluid mechanics, a sting is a test fixture on which models are mounted for testing, e.g. in a wind tunnel. A sting is usually a long shaft attaching to the downstream end of the model so that it does not much disturb the flow over the model. The rear end of a sting usually has a conical fairing blending into the (wind tunnel) model support structure. For minimum aerodynamic interference a sting should be as long as possible and have as small a diameter as possible, within the structural safety limits. Critical length of a sting (beyond which its influence on the flow around the model is small) is mostly dependent on Reynolds number. If the flow at the rear end of a model (model base) is laminar, the critical sting length can be as much as 12-15 base diameters.A.Pope, "W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Tunnel Model On A Z-sting (schematic)
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hours, to global winds resulting from the difference in absorption of solar energy between the climate zones on Earth. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect). Within the tropics and subtropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds; in areas that have variable terrain, mountain and valley breezes can prevail. Winds are commonly classified by their spatial scale, their speed and direction, the forces that cause them, the regions in which they occur, and their effect. Winds have various aspe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Mechanics
Fluid mechanics is the branch of physics concerned with the mechanics of fluids ( liquids, gases, and plasmas) and the forces on them. It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical and biomedical engineering, geophysics, oceanography, meteorology, astrophysics, and biology. It can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion. It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a ''macroscopic'' viewpoint rather than from ''microscopic''. Fluid mechanics, especially fluid dynamics, is an active field of research, typically mathematically complex. Many problems are partly or wholly unsolved and are best addressed by numerical methods, typically using computers. A modern discipline, called computational fluid dynamics (CFD), is dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Test Fixture
A test fixture is an environment used to consistently test some item, device, or piece of software. Test fixtures can be found when testing electronics, software and physical devices. Electronics In testing electronic equipment such as circuit boards, electronic components, and chips, a test fixture is a device or setup designed to hold the device under test in place and allow it to be tested by being subjected to controlled electronic test signals. Examples are a bed of nails tester or SmartFixture. Electronics Test Fixture.jpg, Side connectors, centering pins, test needles, pre-centering parts. Functional Test Fixture for electroncis.jpg, A functional test fixture is a complex device to interface the device under test (DUT) to the automatic test equipment (ATE). Software A software test fixture sets up a system for the software testing process by initializing it, thereby satisfying any preconditions the system may have. For example, the Ruby on Rails web framework uses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Tunnel
Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft will fly. NASA uses wind tunnels to test scale models of aircraft and spacecraft. Some wind tunnels are large enough to contain full-size versions of vehicles. The wind tunnel moves air around an object, making it seem as if the object is flying. Most of the time, large powerful fans suck air through the tube. The object being tested is held securely inside the tunnel so that it remains stationary. The object can be an aerodynamic test object such as a cylinder or an airfoil, an individual component, a small model of the vehicle, or a full-sized vehicle. The air moving around the stationary object shows what would happen if the object was moving through the air. The motion of the air can be studied in different ways; smoke or dye can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynolds Number
In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow ( eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AGARD-B Wind Tunnel Model
AGARD-B is a standard wind tunnel model (calibration model) that is used to verify, by comparison of test results with previously published data, the measurement chain in a wind tunnel. Together with its derivative AGARD-C it belongs to a family of AGARD standard wind tunnel models. Its origin dates to the year 1952, and the Second Meeting of the AGARD Wind Tunnel and Model Testing Panel in Rome, Italy, when it was decided to define two standard wind tunnel model configurations (AGARD-A and AGARD-B) to be used for exchange of test data and comparison of test results of same models tested in different wind tunnels. The idea was to establish standards of comparison between wind tunnels and improve the validity of wind tunnel tests. Among the standard wind tunnel models, AGARD model configuration B (AGARD-B) has become by far the most popular. Initially intended for the supersonic wind tunnels, the AGARD-B configuration has since been tested in many wind tunnels at a wide range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Tunnel Balance
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hours, to global winds resulting from the difference in absorption of solar energy between the climate zones on Earth. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect). Within the tropics and subtropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds; in areas that have variable terrain, mountain and valley breezes can prevail. Winds are commonly classified by their spatial scale, their speed and direction, the forces that cause them, the regions in which they occur, and their effect. Winds have various aspe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
