# Supersonic wind tunnel

Supersonic wind tunnel

A supersonic wind tunnel is a wind tunnel that produces supersonic speeds (1.2<M<5)The Mach number and flow are determined by the nozzle geometry. The Reynolds number is varied changing the density level (pressure in the settling chamber). Therefore a high pressure ratio is required (for a supersonic regime at M=4, this ratio is of the order of 10). Apart from that, condensation or liquefaction can occur. This means that a supersonic wind tunnel needs a drying or a pre-heating facility.A supersonic wind tunnel has a large power demand leading to only intermittent operation.

Restrictions for supersonic tunnel operation

Minimum required pressure ratio

Optimistic estimate:Pressure ratio $leq$ the total pressure ratio over normal shock at M in test section:

$frac\left\{P_t\right\}\left\{P_\left\{amb leqleft\left(frac\left\{P_\left\{t_1\left\{P_\left\{t_2 ight\right)_\left\{M_1=M_m\right\}$

Examples:

Temperature effects: condensation

Temperature in the test section:

$frac\left\{T_m\right\}\left\{T_t\right\}=left\left(1+frac\left\{gamma-1\right\}\left\{2\right\}M_m^2 ight\right)^\left\{-1\right\}$

with $T_t$ = 330K: $T_m$ = 70K at $M_m$ = 4

The Mach range is limited by reservoir temperature

Power requirements

The power required to run a supersonic windtunnel is enormous, of the order of 50 MW per square meter of test section. For this reason most wind tunnels operate intermittently using energy stored in high-pressure tanks. These windtunnels are also called intermittent supersonic blowdown wind tunnels (of which a schematic preview is given below). Another way of achieving the huge power output is with the use of a vacuum storage tank. These tunnels are called indraft supersonic wind tunnels.Other problems operating a supersonic wind tunnel include:
*enough supply of dry air
*wall interference effects
*fast instruments needed for intermittent measurements

Tunnels such as a Ludwieg tube have short test times (usually less than one second), relatively high Reynolds number, and low power requirements.

*

ee also

* Wind tunnel
* Low speed wind tunnel
* High speed wind tunnel
* Hypersonic wind tunnel
* Ludwieg tube
* Shock tube

* [http://arc.uta.edu/videos_files/SWT_12202007.wmv "UTA supersonic wind tunnel test(Video)"]

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Wind tunnel — A wind tunnel is a research tool developed to assist with studying the effects of air moving over or around solid objects.Ways that wind speed and flow are measured in wind tunnels: * Threads can be attached to the surface of study objects to… …   Wikipedia

• wind tunnel — /wind/, Aeron. a tubular chamber or structure in which a steady current of air can be maintained at a controlled velocity, equipped with devices for measuring and recording forces and moments on scale models of complete aircraft or of their parts …   Universalium

• Hypersonic wind tunnel — A hypersonic wind tunnel is designed to generate a hypersonic flow field in the working section. The speed of these tunnels vary from Mach 5 to 15. As with supersonic wind tunnels, these types of tunnels must run intermittently with very high… …   Wikipedia

• Subsonic and transonic wind tunnel — ubsonic tunnelLow speed wind tunnels are used for operations at very low mach number, with speeds in the test section up to 400 km/h ( 100 m/s, M = 0.3). They are of open return type ( losses. Open wind tunnelThe working principle is based on the …   Wikipedia

• Trisonic wind tunnel — The Trisonic Wind Tunnel (TWT) is a wind tunnel in El Segundo, California. It was built by North American Aviation in the 1950s. This tunnel is so named because it is capable of testing in three speed regimes subsonic, transonic, and supersonic,… …   Wikipedia

• wind tunnel — A tubelike structure or passage, sometimes continuous, which together with its adjuncts (such as a fan), produces a high speed movement of air or other gas. Objects such as engines or aircraft, airfoils, rockets (or models of these objects), etc …   Aviation dictionary

• Supersonic transport — The Concorde supersonic transport had an ogival delta wing, a slender fuselage and four underslung Rolls Royce/Snecma Olympus 593 engines. A supersonic transport (SST) is a civilian supersonic aircraft designed to transport passengers at speeds… …   Wikipedia

• Eight-Foot High Speed Tunnel — Infobox nrhp name = Eight Foot High Speed Tunnel nrhp type = nhl caption = The turning vanes of the Eight Foot High Speed Tunnel lat degrees = 37 lat minutes = 4 lat seconds = 49 lat direction = N long degrees = 76 long minutes = 20 long seconds …   Wikipedia

• Full Scale 30- by 60-Foot Tunnel — Infobox nrhp name = Full Scale Wind Tunnel nrhp type = nhl caption = Open test section of the Full Scale Wind Tunnel lat degrees = 37 lat minutes = 4 lat seconds = 51 lat direction = N long degrees = 76 long minutes = 20 long seconds = 30 long… …   Wikipedia

• Diverterless supersonic inlet — Testing of the F 35 Diverterless Supersonic Inlet on an F 16 testbed. The original intake is shown in the top image. A diverterless supersonic inlet (DSI) is a type of jet engine air intake used by some modern combat aircraft to control air flow… …   Wikipedia