(redirected from blow the whistle)
Also found in: Dictionary, Thesaurus, Medical, Idioms, Wikipedia.


1. a device for making a shrill high-pitched sound by means of air or steam under pressure
2. Music any pipe that is blown down its end and produces sounds on the principle of a flue pipe, usually having as a mouthpiece a fipple cut in the side



a generator that converts the energy of a fluid stream into the energy of acoustic vibrations. Unlike a siren, a whistle has no moving parts and is therefore simpler to manufacture and use. Depending on the working fluid for which they are designed, whistles are classified as gas-jet or jet liquid. Gas-jet whistles in turn are subdivided into low- and high-pressure types. As a rule, low-pressure whistles have a relatively high efficiency but generate little power, and until recently they were used only for signaling. However, with methods for increasing power output, uses have now been found for whistles in industry, for example, in the coagulation of aerosols and in the acceleration of processes of heat and mass transfer.

The simplest low-pressure whistle is the familiar lip whistle, which consists of a slotted inlet and a resonance chamber, usually cylindrical in shape. Air fed into the inlet is split into two streams by the sharp edge of the resonator. One stream exits into the surrounding medium, while the other enters the resonance chamber, thereby increasing the pressure. After a period of time that depends on the size of the chamber, the second stream interrupts the main flow, as a result of which there is a periodic compression and rarefaction of the air that is propagated as acoustic waves. Lip whistles ordinarily operate at air pressures not exceeding 1.4 atmospheres and generate acoustic power of the order of 1 watt. Some designs enable several kilowatts of power to be generated.

The ultrasonic Galton whistle and vortex whistles are further examples of low-pressure devices. Vortex whistles have a cylindrical chamber into which a gas or liquid is introduced tangentially. A narrow tube extends along the axis of the chamber, and it is through this tube that the gas exits, radiating sound energy. Elastic vibrations are induced by a combination of the pressure decrease along the whistle axis that results from vortex motion and the periodic pressure equalization that results from the rush of gas from the atmosphere into the tube’s outlet. At frequencies up to 30 kilohertz, the power output of a vortex whistle is usually of the order of several watts. A representative high-pressure whistle is the Hartmann generator, which has a maximum power output of 0.5 kilowatt.

The design and operating principles of jet liquid whistles are analogous to those of the gas-jet type. The most common are lamellar jet liquid whistles, which function by using a liquid stream under high pressure to excite resonant vibrations of the vibrator—a blade or rod.


Shkol’nikova, P. Sh. “Vozdukhostruinye generatory akusticheskikh kolebanii dlia koaguliatsii aerozolei.” Akusticheskii zhurnal, 1963, vol. 9, no. 3, pp. 368–75.
Bergmann, L. Ul’trazvuk i ego primenenie v nauke i tekhnike, 2nd ed. Moscow, 1957. (Translated from German.)


References in periodicals archive ?
All too often this leads to them being fired, and the fired employee decides to blow the whistle in retaliation.
Fourteen percent cited concerns about negative media coverage about whistleblowers as a reason why they wouldn't blow the whistle.
Blow the whistle on yourself or your team before someone else does it for you.
Earlier studies are not clear on why employees blow the whistle, exploring factors such as age, gender and time on the job, but providing inconsistent results, according to the new report.
Furthermore, based on additional research about attribution theory, we believe that anger will play an important role in motivating decisions to blow the whistle.
Whistleblowers have often claimed that cash rewards or financial incentives had no impact on their decision to blow the whistle, and Miceli and Near further report that very few federal employees said that cash awards would encourage them to blow the whistle.
Mr Smart said: "Despite plenty of evidence to show that whistleblowers are one of the best ways to identify and stop fraud, many employees in Europe fear reprisals, even loss of employment, if they do blow the whistle.
I recently caught my boss with his hands in the till but am afraid I will lose my job if I blow the whistle.
The answer may be difficult to do but is necessary-they need to blow the whistle.
I don't want to blow the whistle on a workmate but I don't agree with what he's doing no matter how hurt he is.
However, in August, leading wholesalers unanimously told The Grocer they would be prepared to blow the whistle on illegal rivals.
If the justices ultimately decide the answer is no, some experts warn that government employees who want to blow the whistle on corruption and malfeasance will have no weapon against retaliation.