Wind Tunnels :: essays research papers

Wind TunnelsIn this report I will talk about the wind cut into. I will described what they ar used for. The different types of wind tunnels from the slow speed subsonicto the high speed hypersonic tunnels. I will also give A few examples of thewind tunnels used today.The wind tunnel is a device used by many people, from High school studentsto NASA engineers. The wind tunnel is a device used to test planes to see howwell it will do under certain conditions. The plane maybe as big as a full size747 or as sm completely as a match. To understand how a wind tunnel is used to help inthe invention process you have to know how a wind tunnel works.How Wind Tunnels WorkA wind tunnel is a machine used to vaporize aircrafts, missiles, engines, androckets on the ground under pre-set conditions. With a wind tunnel you can chosethe air speed, pressure, altitude and temperature to name a few things. A windtunnel is usually has a tube like appearance with which wind is produced by alarge fan to decrease over what they are testing (plane, missiles, rockets, etc.)ora standard of it. The object in the wind tunnel is fixed and placed in the testsection of the tunnel and instruments are placed on the model to record theaerodynamic forces acting on the model.Types of Wind TunnelsThere are four basic types of wind tunnels. Which are low subsonic,transonic, supersonic, and hypersonic. The wind tunnels are class by theamount of speed they can produce. The subsonic has a speed lower then the speedof sound. The transonic has a speed which is about equate to the speed of sound(Mach 1 760 miles per hour at sea level). . The supersonic (Mach 2.75 to 4.96)has a speed of about five times the speed of sound And the fasts of them all thehypersonic (Mach39.5) which has a speed of more then 30,000 miles per hour.Wind Tunnel TestThere are basically two types of wind tunnel test which are staticstability and the pressure test. With these two test you can determine theaerodynamic characterist ics of the aircraft. The static stability test themeasures the forces moments due to the external characteristic. These forcesinclude axial, berth and normal force, rolling, pitching and yawing moment. Thisforces are found by using a strain gauge which is located on the externalportion of the plane. It measures the external flow fields. Then the shadowgraphis used to show the shock waves and flow fields at a certain speed or angle of