Types of Wind Tunnel

Types of Wind Tunnel

Wind tunnels can be classified based on air flow speed in test section and based on shape. Based on Flow Speed:

1. Subsonic or low speed wind tunnels: Maximum flow speed in this type of wind tunnels can be 135m/s. Flow speed in wind tunnels is enerally preferred in terms of Mach number which comes out to  be around !." for this case. case. #his type of wind tunnels tunnels are most cost effecti$e due to to the simplicity of the desin and low wind speed. %enerally low speed wind tunnels are found in schools and uni$ersities because of low budet. &. #ransonic wind tunnels: Maximum $elocity in test section of transonic wind tunnels can reach upto speed of sound ie 3"!m/s or Mach number of 1. #hese wind tunnels are $ery common in aircraft industry as most aircrafts operate around this speed. 3. Supersonic wind tunnels: 'elocity of air in test section of such wind tunnels can be upto Mach 5. #his is accomplished usin con$erent ( di$erent no))les. *ower re+uirements for such wind tunnels are $ery hih. ". ,ypersonic wind tunnels: Wind $elocity in test section of such type of wind tunnels can measure between Mach 5 and Mach 15. #his is also achie$ed usin con$erent ( di$erent no))les. Based on Shape:

1. -pen circuit wind tunnel: #his type of wind tunnel is open at both ends. #he chances of dirt particles enterin with air are more so more honeycombs meshe to clean incomin air are re+uired to clean the air. -pen type wind tunnels can further be di$ided into two cateories:

a Suc0down tunnel: With the inlet open to atmosphere axial fan or centrifual  blower is installed after test section. #his type of wind tunnels are not preferred  because incomin air enters with sinificant swirl.  b 2lower tunnel:  blower is installed at the inlet of wind tunnel which throws the air into wind tunnel. swirl is a problem in this case as well but blower tunnels are much less sensiti$e to it. &. 4losed circuit wind tunnel: -utlet of such wind tunnel is connected to inlet so the same air circulates in the system in a reulated way. #he chances of dirt enterin the system are also $ery low. closed wind tunnels ha$e more uniform flow than open type. #his is usually a choice for lare wind tunnels as these are more costlier than open type wind tunnels.

ead more: http://www.brihthub.com/en$ironment/renewable( enery/articles/16666.aspx7ix))18!lbf,nb What Are Wind Tunnels? 04.27.10

irplane builders use 9S wind tunnels to test new airplane desins. mae 4redit: 9S 'iew ;arer mae <

Wind tunnels are large tubes with air moving inside. The tunnels are used to copy the actions of an object in flight. 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 big enough to hold full-sie versions of vehicles. The wind tunnel moves air around an object! ma"ing it seem li"e the object is really flying.

How Do Wind Tunnels Work?

#ost of the time! powerful fans move air through the tube. The object to be tested is fastened in the tunnel so that it will not move. The object can be a small model of a vehicle. $t can be just a piece of a vehicle. $t can be a full-sie aircraft or spacecraft. $t can even be a common object li"e a tennis ball. The air moving around the still object shows what would happen if the object were moving through the air. %ow the air moves can be studied in different ways. Smo"e or dye can be placed in the air and can be seen as it moves. Threads can be attached to the object to show how the air is moving. Special instruments are often used to measure the force of the air on the object.

 wind tunnel test shows how a tennis ball mo$es throuh the air. mae 4redit: 9S 'iew ;arer mae <

How Does NASA Use Wind Tunnels for Aircraft? NASA has more wind tunnels than any other group. The agency uses the wind tunnels in a lot of ways. &ne of the main ways NASA uses wind tunnels is to learn more about airplanes and how things move through the air. &ne of NASA's jobs is to improve air transportation. Wind tunnels help NASA test ideas for ways to ma"e aircraft better and safer. (ngineers can test new materials or shapes for airplane parts. Then! before flying a new airplane! NASA will test it in a wind tunnel to ma"e sure it will fly as it should. NASA also wor"s with others that need to use wind tunnels. That way! companies that are building new airplanes can test how the planes will fly. )y letting these companies use the wind tunnels! NASA helps to ma"e air travel safer.

How Can Wind Tunnels Help Spacecraft? NASA also uses wind tunnels to test spacecraft and roc"ets. These vehicles are made to operate in space. Space has no atmosphere. Spacecraft and roc"ets have to travel through the atmosphere to get to space. *ehicles that ta"e humans into space also must come bac" through the atmosphere to (arth. Wind tunnels are important in ma"ing the new Ares roc"ets and &rion spacecraft. Ares and &rion are new vehicles that will ta"e astronauts into space. NASA engineers tested ideas for the design of Ares in wind tunnels. They needed to see how well Ares would fly. (ngineers tested &rion models. They needed to "now what would happen to different designs when the spacecraft came bac" through the atmosphere.

 9S is usin wind tunnels to test the desin of the new res  roc0et. mae 4redit: 9S 'iew ;arer mae +ong after the first design wor" is finished! NASA can still use wind tunnels. Wind tunnel tests have helped NASA change

the space shuttle to ma"e it safer. Wind tunnels will "eep helping ma"e all spacecraft and roc"ets better.

Wind tunnels can even help engineers design spacecraft to wor" on other worlds. #ars has a thin atmosphere. $t is important to "now what the #artian atmosphere will do to vehicles that are landing there. Spacecraft designs and parachutes are tested in wind tunnels set up to be li"e the #artian atmosphere.

What Types of Wind Tunnels Does NASA Use? NASA has many different types of wind tunnels. They are located at NASA centers all around the country. The wind tunnels come in a lot of sies. Some are only a few inches s,uare! and some are large enough to test a full-sie airplane. Some wind tunnels test aircraft at very slow speeds. )ut some wind tunnels are made to test at hypersonic speeds. That is more than ! miles per hour/