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 ?
When his Royal Highness came into our showroom, I showed him a labrador whistle and said 'This wouldn't do for your spaniels'.
We raced back when the whistle sounded from school.
amp;nbsp;"Women without a whistle - real or metaphoric - would 'expose themselves' and if they're assaulted and no one does anything, it would be their fault for not whistling.
The new Whistle board will include Claire Gething, who has been promoted to director, and Whistle's previous chairman Matt Fleming, who will be a minority shareholder and non-executive director.
In Dog Whistle Politics: How Coded Racial Appeals Have Reinvented Racism & Wrecked the Middle Class, Lopez illustrates how politicians use coded racial appeals to influence social discourse, win elections, suppress liberalism, weaken the middle class, push their own agendas, and serve the interests of wealthy Americans.
Before beginning whistle training, you need to decide which type of whistle you want to use.
Chaudhry said under the United Nations Convention Against Corruption (UNCAC), legislation on Whistle Blowing is an obligation on Pakistan.
Qamar Zaman Chaudhry said that proposed Whistle Blowing Bill will help people who are courageous and prepared to lift the lid on corrupt practices in the Country.
Whistle also announced the close of a USD 15m series B financing round led by Nokia Growth Partners and joined by new investors Qualcomm; Melo7 Tech Partners, LLC, a fund co-founded by Carmelo Anthony and Stuart Goldfarb; and Queensbridge Venture Partners, founded by Nasir "Nas" Jones.
The Whistle can be used equally effectively in a number of different settings, including outdoors during sporting events and hunting trips.
CARDIFF Devils head coach Dave Whistle is ready to fly back to the UK from North America at the end of June to attend the Elite League ice hockey fixtures meeting.
A SIMPLE tin whistle was proudly produced at the Roadshow by the family of a youth whose life it briefly saved.