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Product Information
Shock Tube:
Conventional high pressure driven shock tube shown schematically in the figure below consists of a constant area tube divided in to driver and driven sections separated by a diaphragm. On one side of the diaphragm, a gas is filled to a pressure high enough to rupture the metal diaphragm, and pressure in the other tube is reduced to a lower value than atmospheric pressure as required. The former is termed the driver side and the latter the driven side. When the diaphragm ruptures due to the high pressure gas in the driver tube, it generates a shock wave that moves along the length of the driven tube, thereby increasing the pressure, temperature and density of the driven gas. In a shock tube, the gas filled in the driven section is the test gas under consideration.


 
Reddy Tube:
This is a revolutionary table top devise invented by Prof. K P J Reddy where the shock waves are produced by hand driven piston without any hazardous effects associated with the conventional shock tubes. The high pressure required for rupturing the diaphragm to produce a shock wave is generated inside the driver tube by pushing a piston akin to the plunger in a medical syringe. The importance of this devise is its versatility and ease of operation. In addition to being a good practical devise for teaching shock waves and compressible aerodynamics Reddy tube has been applied for artificial insemination of cattle, investigation of brain injuries in accidents, removal of brain tumour, water purification, oil extraction from medicinal plants and even for making tasty pickles by many researchers and students. Details of the Reddy tube with associated instrumentation suitable for carrying out many experiments in the laboratory are shown in the accompanying figure. Shock Mach numbers of up to 1.5 are easily produced with air as the driver gas while higher value shock Mach numbers (stronger shock waves) can be produced by using helium gas as the driver gas.
Technical Specifications Working Parameters
Diameter : 29 mm
Driver tube length : 400mm
Driven tube length : 600mm
Diaphragm material : paper
Diaphragm rupture pressure : Up to 7 bar (manual).
Initial driven side pressure : 200 – 760 mm of Hg.
Primary shock Mach number range : 1.3 – 2.0
Instrumentation
Diaphragm rupture pressure monitor.
High speed pressure sensors for measurement of
 
Shock speed
Pressures behind primary shock wave
Pressure behind reflected shock wave
Data acquisition oscilloscope.
List of experiments
Dynamic calibration of sensors – Shock waves can be used to conduct dynamic calibration of piezoelectric or piezoresistive pressure sensors and accelerometers so as to figure out the maximum frequency response of the device. This becomes an important parameter when the measurement involves highly fluctuating input, such as pressure measurements inside a combustion chamber.

Projectile launcher – Shock waves can be used to propel small projectiles with high velocities in excess of Mach 1. The effect of impact of such a projectile of certain materials leads to an interesting field of research. Such an impact has the ability to change the properties of the material. Studies in this regard will help in creating workarounds for unwanted impact on fast moving aircrafts.

Shock impact on materials – Impact of strong shocks on hard materials such as ceramics causes physical and chemical changes on its surface, even change in surface morphology. Studies into this field would be critical in designing heat shields for re-entry satellite vehicles etc.
Investigation of Traumatic brain injury – Injuries due to sudden impact on the head can be replicated using shock waves. These experiments are generally carried out on laboratory rats, which are later dissected and checked for growth of the trauma.
Understanding the Fundamental physics – This involves understanding the mechanisms at work within the shock thickness, thermal and chemical non- equilibrium of gas behind strong shock waves, shock focussing and attenuation, shock movement of gas behind strong shock waves, shock movement over uneven surfaces and in bending tubes, shocks in rarefied and chemically reacting flows.
The Reddy tube is capable of conducting research on any aspect of shock waves with the limitation of the upper limit of shock strength
Customizations Available
Table-top gas driven shock tube.
The physical dimensions of this instrument is similar to the Reddy tube. Working pressures of 100 atmospheres or even higher can be obtained. Shock Mach numbers up to 3.5 – 4 can be achieved. This instrument can be used as a full on research tool into shock waves.
Full scale shock tube
This instrument is at least 6 m in length. Working pressures can be up to 200 bar or higher. Shock Mach numbers up to 5 can be achieved. Experiments of shock wave visualization can be conducted.