TEXT IA WIND TUNNELS Wind Tunnel is a tube like structure where wind is produced usually by a large fan to flow over the test object. <...> The object is connected to instruments that measure and record aerodynamic forces that act upon it. <...> Wind tunnels are usually designed for a specific purpose and speed range. <...> There are special tunnels for propulsion, icing research, sub4 sonic, supersonic and hypersonic speeds. <...> According to its basic architecture a wind tunnel may be open and draw air from the room into the test section, or the tunnel may be closed with the air recirculating around the circuit. <...> Wind tunnels may be classified according to the air pressure (atmospheric, variable-density), or their size (ordinary ones or full-scale). <...> There are numbers of wind tunnels (meteorological tunnel, shock tunnel, plasma-jet tunnel, hot-shot tunnel, water tunnel) that fall in a special category of their own. <...> The wind tunnel is the most lasting contribution of the Wright brothers to the science of aerodynamics. <...> Wind tunnel testing is the technical support of any major development process involving aerodynamics. <...> Static stability of aircraft and missiles Dynamic stability derivatives of aircraft Surface Pressure distributions on nearly all systems. <...> For shock wave visualizations, the Schlieren photography has been used for many years. <...> The most up-to-date wind tunnels have now sophisticated computer controls. <...> Main components of a tunnel are: entrance cone, test section, regain passage, propeller/motor, return passage. <...> The test section is where the model is placed and held with appropriate struts. <...> The section is generally rectangular (sometimes the test section is an open jet). <...> When the real Reynolds and Mach numbers cannot be reproduced, the experimental data are affected by the so-called scale effect. <...> Sometimes the scale effects are negligible, sometimes (like transonic flows, low speeds) they are not. <...> Among the most well known effects there are the scale effects, the flow 6 blockage, due to the presence of the model in the test section and wall boundary layers. <...> Why is it necessary to measure and record aerodynamic forces <...>
Обучение_чтению_литературы_на_английском_языке_по_специальности_«Аэродинамика»._Часть_2..pdf
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CONTENTS
- .......................................................................................... 3
Unit I ....................................................................................................... 4
Text IA. Wind Tunnels ............................................................................ 4
Text IB. A Few Types of Modern Wind Tunnels .................................... 9
Text IC. How Wind Tunnels Work ......................................................... 12
Text ID. Computer Control and Data Acquisition ................................... 14
Unit II ..................................................................................................... 16
Text IIA. Ballistics .................................................................................. 17
Text IIB. Drag Resistance Modelling and Measuring ............................. 21
Text IIC. More Advanced Drag Models .................................................. 23
Text IID. Forensic Ballistics ................................................................... 25
Unit III .................................................................................................... 26
Text IIIA (part I). Moth in a Wind Tunnel .............................................. 26
Text IIIA (part II). Float Like a Robot Butterfly ..................................... 27
Text IIIB (part I). On the End of a Whirling Arm ................................... 30
Text IIIB (part II). Sir George Cayley ..................................................... 31
Text IIIC Conservation Laws .................................................................. 33
Text IIID .................................................................................................. 35
Supplementary Texts ............................................................................ 36
Text 1 ............................................................................................... 36
Text 2 ............................................................................................... 37
Text 3 ............................................................................................... 39
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