- In a steady streamline flow of an ideal liquid, the sum of all energies present remains constant, provided no work is done by the airflow or on it. In other words, in a horizontal flow the sum of kinetic energy and pressure energy is constant or P + 1/2 ρV2 = K where P is the static pressure, ρ is the density, V is the air speed, and K is a constant. From this law, it follows that where there is a velocity increase in a fluid flow, there must be a corresponding pressure decrease. Thus an airfoil, by increasing the velocity of the flow over its upper surface, derives lift from the decreased pressure. Swiss physicist and mathematician Daniel Bernoulli formulated this theorem in 1738.
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Bernoulli's theorem — 1. Statistics. See law of averages (def. 1). 2. Hydrodynamics. an expression of the conservation of energy in streamline flow, stating that the sum of the ratio of the pressure to the mass density, the product of the gravitational constant and… … Universalium
Bernoulli's theorem — Title used for the ‘law of large numbers’ in probability theory, proved by Jakob Bernoulli (1654–1705). The theorem provides the best known link between probability and the frequency of occurrence of events in a sequence of trials. It is thus… … Philosophy dictionary
bernoulli's theorem — noun Usage: usually capitalized B 1. [after Jacques Bernoulli] : a basic principle of statistics: as the number of independent trials of an event of theoretical probability p is indefinitely increased, the observed ratio of actual occurrences of… … Useful english dictionary
Bernoulli's theorem — Bernoul′li s the′orem n. sta • Etymology: 1920–25; after Jakob Bernoulli … From formal English to slang
bernoulli's Theorem — in stream of liquid, the sum of elevation head, pressure head, and velocity remains constant along any line of flow provided no work is done by or upon liquid on course of its flow; decreases in proportion to energy lost in flow … Dictionary of automotive terms
Bernoulli distribution theorem trial — Ber·noul·li distribution, theorem, trial (bər nooґle) (bār noo eґ) [Jakob Bernoulli, Swiss mathematician, 1654â€“1705] see under distribution, theorem, and trial … Medical dictionary
Bernoulli's principle — n. 〚after BERNOULLI Daniel〛 the statement that an increase in the speed of a fluid produces a decrease in pressure and a decrease in the speed produces an increase in pressure * * * or Bernoulli s theorem Principle that relates pressure, velocity … Universalium
Bernoulli's principle — This article is about Bernoulli s principle and Bernoulli s equation in fluid dynamics. For Bernoulli s Theorem (probability), see Law of large numbers. For an unrelated topic in ordinary differential equations, see Bernoulli differential… … Wikipedia
theorem — theorematic /thee euhr euh mat ik, thear euh /, adj. theorematically, adv. /thee euhr euhm, thear euhm/, n. 1. Math. a theoretical proposition, statement, or formula embodying something to be proved from other propositions or formulas. 2. a rule… … Universalium
Bernoulli, Daniel — ▪ Swiss mathematician born Feb. 8 [Jan. 29, Old Style], 1700, Groningen, Neth. died March 17, 1782, Basel, Switz. the most distinguished of the second generation of the Bernoulli family of Swiss mathematicians. He investigated not only… … Universalium