Flow Rate

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flow rate

[′flō ‚rāt]
(fluid mechanics)
Also known as rate of flow.
Time required for a given quantity of flowable material to flow a measured distance.
Weight or volume of flowable material flowing per unit time.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Flow Rate


in hydraulics, the volume of fluid flowing through a cross section of a stream per unit time. The flow rate Q of a fluid for a given cross section ω is determined by the formula

Q = ∫ωu dω

where u is the flow velocity within the limits of d, an elementary segment of the cross section. In steady flow, the flow rate of a dropping liquid is constant along a given stream. The average flow velocity of the fluid can be determined from the known values of the flow rate and cross-sectional area: v = Q/ω. The mass of fluid flowing per unit time through a cross section of the stream is called the mass flow rate M. This rate is related with the volume flow rate by the equation M = ρ Q, where ρ is the density of the fluid. The flow rate of a fluid is measured with water meters, measuring spillways, hydrometers, rate-of-flow meters, and other instruments.


Al’tshul’, A. D., and P. G. Kiselev. Gidravlika i aerodinamika. Moscow, 1965.
Chugaev, R. R. Gidravlika, 2nd ed. Leningrad, 1970.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
In this study, case analysis of the blower was carried out with the CFD simulation in order to obtain a maximum flow rate of 400 CMH (14,126 [ft.sup.3]/h.
In the present study, the efficacy of fluid warming decreased as the flow rate increased.
Han, "Effect of oxygen flow rate on ITO thin films deposited by facing targets sputtering," Thin Solid Films, vol.
The mathematical model enables estimation of the regulated pressure as a function of flow rate and inlet pressure (see (2)) [4].
Routine nursing documentation per HD unit protocol provided the following data for each patient during each treatment according to their treatment run log: hourly Qb, pre- and post-dialysis blood pressure, weight gain, target fluid loss, dialysate flow rate, needle gauge, cannulation site and any cannulation difficulties, hourly and cumulative Kt/V, intradialytic complications, and dialysis duration.
According to the criterion of susceptibility of the emitters to reduced flow (BARROS et al., 2009), it appeared that only the emitter E4 showed variation, with Qr exceeding 10%, characterized as being susceptible to flow rate reduction.
This sample group is comparable to that of our study; however, they used maximum flow rate of 15 mL/sec as cut-off point, which was not the case in our study.
This study shows there are differences in salivary flow rate after stimulation of chewing pineapple (Ananascomocus) and papaya (Carica papaya), with a flow rate of saliva after chewing pineapple (Ananascomocus) higher than after chewing papaya (Carica papaya).
4) Altering the hot water temperature from 29[degrees]C to 43[degrees]C, retaining the flow rate of water at 54 kg/hr and packing density at 110 [m.sup.2]/[m.sup.3].
The examination of the grid convergence was performed considering the flow rate of 1.0 kg/s at exit, with 5.8 mm gap width and a fine meshing of 8.8 million elements and a range of course meshing whose grids are 4.1 million, 1.8 million, and 0.75 million elements.