Supersonic wind tunnels are those where air speeds simulated are more than the speed of sound. The speed of sound at standard temp is around 340m/sec. The energy of wind at these speeds is very large and hence the energy required even to run a 25mm x 25mm tunnel continuously requires about 50k watts of power. Hence most of the Supersonic Wind tunnels are intermittent tunnels. The air is blown from high pressure to a small pressure for short period of time. Most Supersonic tunnels store energy in high pressure reservoirs and blow the air down the test duct to atmosphere. The design of Supersonic Wind tunnel depends on largely the following criteria.

• Test duct size
• Mach Number range
• Run time (Duration of flow supersonic)
• Test duct size

Maximum pressure of the reservoir