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Topic: Friction factor

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	Technical Articles: Water Velocity: It's Impact on Accuracy of Hydraulic Calculations (Site not responding. Last check: 2007-11-02)
		For instance, the friction factor is not a constant for the same pipe material but changes with the water velocity as well as the pipe diameter.
		The typical method for determining the friction factor is the use of the Moody diagram (see Figure 1).
		Friction factors were based on the relative roughness for new pipe which is determined by dividing the specific roughness by the pipe diameter.
	www.sprinklernet.org /technical/articles/watervelocity.html (1881 words)

	Transport Canada - TDC - TP 12584E - Summary (Site not responding. Last check: 2007-11-02)
		Relative to a wet asphalt surface at -2°C, the friction factor was approximately 0.15 (15%) less on asphalt contaminated with a Type II fluid, 0.25 (25%) less on a mixture of Type II and potassium acetate, and 0.38 (38%) less on a mixture of Type II and urea.
		Relative to a wet concrete surface at -2°C, the friction factor was 0.13 (30%) less on concrete contaminated with Type II Ultra, and 0.20 (49%) less on Type II Octagon and a mixture of Type II fluid and potassium acetate.
		The friction factor decreased by up to 0.20 (22%) and 0.10 (14%) for Octagon and Ultra Type II fluids respectively when the application rate was increased by 100 fold on asphalt.
	www.tc.gc.ca /TDC/summary/12500/12584e.htm (1255 words)

	The tunnel Page - Lambda calculation from pressure measurements (Site not responding. Last check: 2007-11-02)
		The wall friction factor is defined as an average factor for the tunnel which includes all singular losses between the tunnel portals in addition to the friction along the wall and the road surface.
		The accuracy of the wall friction factor found by this method, should be tested by calculating air-velocity curves with a little lower and higher lambda-value and looking at the conformity between the measured and calculated curves.
		By using the calculated wall friction loss on the first thousand meters of the tunnel as a new basic line, the influence of wall friction is removed and the pressure increase from each group of fans is clearly illustrated in fig.
	home.no.net /lotsberg/artiklar/ventilation/fodnes.html (1711 words)

	ME 354 - Lab 3 - Minor Losses Experiment
		Whereas the Darcy-Weisbach equation is valid for both flow regimes, the form of the functional relationship for the friction factor is dependent on the type of flow.
		An accepted practice is to determine the friction factor from the Moody chart for pipe friction.
		Friction factor and head loss for the straight section of pipe may be determined directly from equation 1.
	www2.latech.edu /~hhegab/pages/me354/Lab3/Lab3_minorlosses_Sp99.htm (1572 words)

	Spirax Sarco Learning Centre: 10.2 - Steam Distribution: Pipes and Pipe Sizing
		Matching the wrong equation to the wrong friction factor will result in a 400% error and it is therefore important that the correct combination of equation and friction factor is utilised.
		However, Equation 10.2.3 is difficult to use because the friction factor appears on both sides of the equation, and it is for this reason that manual calculations are likely to be carried out by using the Moody chart.
		45 m³/h at 15°C. In essence, the friction factor depends on the Reynolds number (Re) of the flowing liquid and the relative roughness (kS/d) of the inside of the pipe; the former calculated from Equation 10.2.6, and the latter from Equation 10.2.7.
	spiraxsarco.com /learn/html/10_2_01.htm (3498 words)

	Coefficients Of Friction
		The coefficient of sliding friction is expressed using the same formula as the static coefficient and is generally lower than the static coefficient of friction..
		The coefficient of friction is required in calculating tightening torques and resulting bolt tensile forces and stress and in calculating the resulting friction between the connected surfaces.
		The coefficient of friction used for designing these types of connections is dependent on the interface pressure, materials, surface condition, surface coatings etc. The coefficient of friction is also dependent on the method of installation.
	www.roymech.co.uk /Useful_Tables/Tribology/co_of_frict.htm (1591 words)

	Parameter editor (Site not responding. Last check: 2007-11-02)
		The friction factor is the amount by which the work done by friction on those bounding shells that are in contact is weighted.
		Sticking friction is a flag which denotes whether to use sticking friction on the interface between the die and the workpiece or to use a Tresca sliding friction model.
		A value of 1 is the `on' position, where sticking friction is used and the friction factor is ignored.
	www.bath.ac.uk /mech-eng/fsu/fmppage/reports/fmp24/node9.html (994 words)

	Darcy friction factor - Wikipedia, the free encyclopedia
		The Darcy friction factor is a dimensionless number used in internal flow calculations.
		It expresses the linear relationship between mean flow velocity and pressure gradient.
		The factor is named after French engineer Henry Darcy.
	en.wikipedia.org /wiki/Darcy_Friction_factor (68 words)

	Friction
		Absent friction, the bottom plate of the levitator would continue rising closer and closer to the underside of the table.
		Friction, however, absorbs momentum and becomes the limiting factor that determines the eventual equilibrium gap.
		Then, dynamic viscosity [mu] is the interlamellar stickiness or friction between the sheets and also indicates how much a fluid particle is likely to be affected by aberrations in the movements of adjacent particles.
	www.seykota.com /rm/friction/friction.htm (1312 words)

	Structural engineering other topics - soils friction factor
		is dead-on correct: the soil/concrete friction angle seldom controls the design; the actual failure surface (in most soils) is usually millimeters to centimeters away from the soil/concrete interface (in the absence of weak zones, that is.) This is true for footings, retaining walls, grouted tiebacks, driven piles and drilled piers.
		If the friction factor is this low, sliding can easily control the design, and the retaining wall footing will be as long as the wall is high.
		I think that one thing that prevents the use of a reliably established friction angle or friction factor is the number of tests required to determine the value for which there is a 5% probability of being exceeded.
	www.eng-tips.com /viewthread.cfm?qid=75349 (2278 words)

	Experiment 100. Pipe Flow.
		Several friction factor equations are available for systems of flow depending on the type of flow present (laminar or turbulent) and the interior surfaces through which the flow takes place.
		This is done for water by obtaining waters density and viscosity at the operating temperatures, the interior diameter of the pipe, and the roughness coefficient of the pipe.
		The relationship seen between the friction factor and the Reynolds number for turbulent suggest that at large flow rates the friction factor becomes less dependent on the Reynolds number.
	www.eng.fsu.edu /~schreiber/uol/exp100 (1758 words)

	Pizza Marketing Quarterly (Site not responding. Last check: 2007-11-02)
		Friction Factor: This is a value used to account for the temperature gain of the dough during the mixing process as a result of friction between the mixing bowl and the dough.
		The friction factor is determined as follows: 3 X the actual dough temperature, minus the sum of the room temperature, flour temperature, and tap water Temperature.
		Special note: The friction factor will need to be calculated for each different size, dough that you make.
	www.pmq.com /mag/2003spring/tom_lehmann.shtml (790 words)

	Baker's Exchange (Site not responding. Last check: 2007-11-02)
		Including a mixer friction factor is necessary because, depending on the mixer, batch size, mixing time and dough consistency, the mechanical action of mixing can add several degrees to the finished dough or batter temperature.
		To arrive at the friction factor, multiply the finished dough or batter temperature by three (or four, for doughs that use a preferment) or by six (for batters).
		So, that particular mixer generates a friction factor of 40 for that dough batch, mixed for the particular amount of time you need for development of that batch size.
	www.bakers-exchange.com /articles/2000/nov.html (1343 words)

	[No title]
		The side friction factor is a unitless value and is equal to the friction force required by the vehicle divided by the component of the vehicle’s weight that is perpendicular to the pavement surface.
		The friction factor used for design of horizontal curves is based on this threshold of driver discomfort rather than the point of impending slip of the vehicle.
		This friction factor was found by determining the safe speed around various curves, where the safe speed was defined as “…the minimum speed at which the centrifugal force, created by the movement of a vehicle around the curve, causes the driver or passenger to feel a side pitch outward.”
	www.mackblackwell.org /research/finals/arc2019/MBTC2019.htm (7092 words)

	[No title] (Site not responding. Last check: 2007-11-02)
		In particular, the invention is applicable to situations wherein parameters such as Reynolds number or frictional properties of the conduit interior that affect the actual flow profile, may be unknown, obscuring the relationship between the ultrasonic signal data and the actual flow rate.
		In one embodiment, the first and second path measurements are combined in accordance with the velocity relationships given by the Pao equation relating velocity profile to friction, to produce a flow measurement which is independent of the friction factor.
		The cancellation of the friction factor from the expression for Q is a consequence of the fact that the geometric variables (y, R) are separable from variables of flow (f).
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/20827.000914&ELEMENT_SET=DECL (3066 words)

	Transport Canada - TDC - TP 13784E - Summary (Site not responding. Last check: 2007-11-02)
		It is well known that surface conditions on roads in wintertime can vary over a wide range on a variety of distance scales reflecting the effect of factors such as: (a) local variations in road conditions and vegetation; and (b) variations in structure (e.g., bridges vs. pavement; intersections and corners vs.
		It is intuitively obvious that less frequent sampling is required to measure the average friction reliably on long, relatively uniform road sections than on short ones or on ones with more variability.
		Numerical analyses have been conducted for a wide range of potential road surfaces to investigate sampling requirements by comparing the friction factor that a device would be expected to measure with the actual friction factor.
	www.tc.gc.ca /tdc/summary/13700/13784e.htm (470 words)

	Inertance Pulse Tube Details (Site not responding. Last check: 2007-11-02)
		The friction factor is somewhat higher than in previous versions of the model because we have incorporated our latest measurements that show more pressure drop for alternating flow than for steady flow.
		This effect is included in the model by calculating the friction factor for the peak velocity reached at each point in the regenerator and using that value to calculate the pressure drop for the entire cycle, even when the velocity goes through zero.
		The flow in the inertance tube is usually turbulent and an appropriate friction factor for turbulent flow (the Blasius eq.) is used at high Reynolds numbers.
	irtek.arc.nasa.gov /IPTdetails.html (2224 words)

	christy's procedure (Site not responding. Last check: 2007-11-02)
		The friction factor is a value determined using Bernoulli's equation which was necessary to find the tube sizes.
		The values obtained for the friction factor and Reynolds number were then placed into a spreadsheet and used to determine what tubes with what lengths and diameters should be used in order to meet our objective.
		From the simultaneous equations we found that the sum of k to be equal to 12.5 and the friction factor to be equal to.0221.
	www.ecsel.psu.edu /~mba127/Project1.htm (1985 words)

	Module 3 Section 2 Page 2
		Several formulations are available to estimate the friction factor for turbulent flows.
		In addition to depending on the Reynolds number the friction factor is a function of the tube surface condition.
		In a circuit the total pressure drop is estimated by the algebraic sum of the distributed losses along the tubes (estimated by 3.12) and the frictional losses (due to singularities such as expansions, contractions, valves, bands, etc.).
	www.iaea.org /ns/nusafe/tutors/thermalhydraulics/module3/learningmaterial/section2p2.htm (146 words)

	IHS ESDU: Data Item 66027
		For circular pipes, calculation methods using a specially developed chart, or values of friction factor from graphs or equations for laminar or turbulent flow are provided.
		For non-circular pipes, including annular and rectangular sections, the equivalent diameter concept is used and correction factors to the circular pipe friction factors are given.
		Data are given for both laminar flow and turbulent flow, for a range of values of natural surface roughness and typical values of roughness for pipes of various materials are given.
	www.esdu.com /graphics/dataitem/66027c.htm (206 words)

	CatalystTutorial
		Perform the CFD calculation with an estimated friction factor for the 1D flow block and either a defined mass flow rate or pressure drop IO boundary setup.
		Calculate the friction factor that should be used to produce the pressure loss - mass flow rate measured data combination.
		Perform another flow rig analysis with this friction factor to confirm the pressure loss and mass flow rate being predicted by the solver.
	www.software.ricardo.com /support/tutorials/vectis/CatalystTutorial.htm (3139 words)

	[No title]
		Firstly, the published friction factor plots are the results of studies of fluid flow through pipes in which the flow is steady and the pipes are of sufficient length that the velocity profile is well established.
		An additional factor which affects the entrance length in turbulent flow is the nature of the entrance itself.
		Friction Factors Some steady-state runs will be made with pipes attached to the entrance assemblies.
	www.eng.buffalo.edu /Courses/ce427/old/TankWord.doc (1411 words)

	Equivalent Lengths
		Since friction factor and Reynolds Number are mainly related to pipe friction, K can be considered to be independent of both friction factor and Reynolds Number.
		Note that this is also true for the friction factor in straight clean commercial steel pipe as long as flow conditions are in the fully developed turbulent zone.
		One can argue that if the fluid is water or a hydrocarbon, the pipeline friction factor would be closer to the friction factor at full turbulence and the error would not be so great, if at all significant; and they would be correct.
	www.cheresources.com /eqlength.shtml (3097 words)

	[No title]
		The friction factors in relation to their corresponding Reynolds numbers were not exactly linear and were also not near the expected values of friction factor on the reference diagram.
		We also determined that friction factor is not only a function of pipe material.
		Conclusion: The purpose lab was to study the effects of friction on head loss and to determine how friction varies in different size pipes and at different rates of flow.
	www.people.virginia.edu /~lrb3f/classes/2004-2005/Hydrology/lab_report4.doc (660 words)

	Wall shear stress (Site not responding. Last check: 2007-11-02)
		In a BWR core the flow is far from isothermal and a thermal boundary layer exists in which the liquid close to the wall has a higher temperature than the liquid further away from the wall.
		This phenomenon implies, due to the decreasing liquid viscosity of water with temperature, that the isothermal friction factor calculated at bulk temperature is higher than the actual friction factor.
		Calculate the frictional pressure drop from the total pressure drop by subtracting the accelerational and gravitational pressure drops for a flow model assumption, eg the homogeneous or separated model.
	www.jakobchr.com /project/node103.shtml (678 words)

	Endless tape cartridge - Patent 4023745
		On the internal area of the disc 4bl is mounted a layer 8 of a material having a small friction factor, such as molybdenum disulfide, carbon, graphite and fluorine-containing resin such as "Teflon (trade name), " by means of coating or molding.
		For example, the friction factor.mu..sub.2 is defined by a value of 2/3 the factor.mu..sub.1.
		Of course, the disc 4b may be separated into more than two areas in a radial direction and the smaller friction of the friction layers is defined on the separate area in the order from the innermost one to the outermost one.
	www.freepatentsonline.com /4023745.html (726 words)

	[No title]
		The friction factor varies in part b and is related to the Reynolds number of the fluid.
		The Colebrook equation, Equation 4, was used to find the friction factor as it changed and then it was reinserted into the code until the pressure was too great.
		Upon completion when the friction factor was a constant 0.02 the resulting time was found to be 152.3 seconds.
	filebox.vt.edu /c/crkim/GEOGRAPHY/writeup.doc (428 words)

	[No title]
		Major losses are represented as: EMBED Equation.3 (1) where v is the velocity of the flowing fluid and f is referred to as the friction factor, which depends on the relative roughness, (/D, and the Reynolds number EMBED Equation.3 .
		The friction factor will be determined for this experiment for both a smooth and rough section of pipe using several different flow rates.
		Since water will be used as both the flowing fluid and the fluid in the manometer, the density terms in equation (2) cancel and, solving for the friction factor, the equation reduces to: EMBED Equation.3 (3) The friction factors are compared to the values obtained from the Moody Chart.
	claymore.engineer.gvsu.edu /~willnerj/egr365/lab11.doc (805 words)

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