Search results
Results from the WOW.Com Content Network
μ is the dynamic viscosity of the fluid (Pa·s = N·s/m 2 = kg/(m·s)); Q is the volumetric flow rate, used here to measure flow instead of mean velocity according to Q = π / 4 D c 2 <v> (m 3 /s). Note that this laminar form of Darcy–Weisbach is equivalent to the Hagen–Poiseuille equation, which is analytically derived from the ...
In fluid dynamics, the Darcy friction factor formulae are equations that allow the calculation of the Darcy friction factor, a dimensionless quantity used in the Darcy–Weisbach equation, for the description of friction losses in pipe flow as well as open-channel flow.
where is the density of the fluid, is the average velocity in the pipe, is the friction factor from the Moody chart, is the length of the pipe and is the pipe diameter. The chart plots Darcy–Weisbach friction factor against Reynolds number Re for a variety of relative roughnesses, the ratio of the mean height of roughness of the pipe to the ...
A number of papers have utilized Darcy's law to model the physics of brewing in a moka pot, specifically how the hot water percolates through the coffee grinds under pressure, starting with a 2001 paper by Varlamov and Balestrino, [6] and continuing with a 2007 paper by Gianino, [7] a 2008 paper by Navarini et al., [8] and a 2008 paper by W ...
A medium with a permeability of 1 darcy permits a flow of 1 cm 3 /s of a fluid with viscosity 1 cP (1 mPa·s) under a pressure gradient of 1 atm/cm acting across an area of 1 cm 2. Typical values of permeability range as high as 100,000 darcys for gravel, to less than 0.01 microdarcy for granite. Sand has a permeability of approximately 1 darcy ...
The Darcy-Weisbach equation can be used equivalently with either the fanning friction factor or the Darcy Weisbach friction factor, however if the fanning factor is used the diameter D in the equation must be replaced with the hydraulic radius.74.60.57.253 04:16, 4 November 2009 (UTC)
First, select the desired pressure loss Δp / L, say 1 kg / m 2 / s 2 (0.12 in H 2 O per 100 ft) on the vertical axis (ordinate). Next scan horizontally to the needed flow volume Q , say 1 m 3 / s (2000 cfm): the choice of duct with diameter D = 0.5 m (20 in.) will result in a pressure loss rate Δ p / L less than the target value.
The hydraulic diameter, D H, is a commonly used term when handling flow in non-circular tubes and channels. Using this term, one can calculate many things in the same way as for a round tube. When the cross-section is uniform along the tube or channel length, it is defined as [1] [2] =, where