An impulse facility is a testing facility that relies on rapid release of stored

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

to generate a short period of high

enthalpy Enthalpy () is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant extern ...

test conditions for testing of

aerodynamic Aerodynamics () is the study of the motion of atmosphere of Earth, air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an ...

flow, aerodynamic heating and

atmospheric reentry Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entry ...

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

chemical kinetics Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a ...

ballistics Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially weapon munitions such as bullets, unguided bombs, rockets and the like; the science or art of designing and acceler ...

, and other effects. The rapid release of energy can result in very high instantaneous energy release rates even though the total energy released is modest. The use of an impulse facility can allow testing of violently energetic phenomena generating temperatures and pressures that no known materials could withstand in steady state. This effect also produces short test times, however, with some types of tests in these facilities lasting less than 100

microsecond A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is to one second, ...

s. Impulse facilities are a special case of blow down facilities where an energy storage mechanism is charged over a period of time and then released to initiate a test and must be charged again before the next test. This contrasts with continuous facilities such as

wind tunnel A wind tunnel is "an apparatus for producing a controlled stream of air for conducting aerodynamic experiments". The experiment is conducted in the test section of the wind tunnel and a complete tunnel configuration includes air ducting to and f ...

s that may run continuously. Examples of impulse facilities are the

shock tube : ''For the pyrotechnic initiator, see Shock tube detonator'' A shock tube is an instrument used to replicate and direct blast waves at a sensor or model in order to simulate explosions and their effects, usually on a smaller scale. Shock tube ...

, the shock tunnel, the expansion tube, the expansion tunnel, and the Ludwieg tube.

References

Engineering equipment {{engineering-stub