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Topic: Strouhal number

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Dimensionless number

Reynolds number

Fluid flow

Richardson number

Potential flow

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Continuous

Prandtl number

Vortex

Mach number

Boussinesq approximation

Incompressible flow

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	Method for low velocity measurement of fluid flow - Patent 5880377
		A constant known as the Strouhal number is used to relate the measured vortex shedding frequency to the fluid flow velocity.
		The Strouhal number is a function of the Reynolds number for the obstruction, which is also a function of fluid flow velocity.
		A dimensionless constant known as the Strouhal number is used to relate the measured vortex shedding frequency to the fluid flow velocity.
	www.freepatentsonline.com /5880377.html (2115 words)

	Strouhal number: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-11-03)
		Mach number (ma) is defined as a ratio of speed to the speed of sound in the medium in case....
		Prandtl number is a dimensionless number approximating the ratio of momentum diffusivity and thermal diffusivity,...
		The weissenberg number is a dimensionless number used in the study of viscoelastic flows....
	www.absoluteastronomy.com /encyclopedia/s/st/strouhal_number.htm (551 words)

	Fluid dynamics - Wikipedia, the free encyclopedia
		Fluid dynamics is the subdiscipline of fluid mechanics that studies fluids (liquids and gases) in motion.
		The discipline has a number of subdisciplines, including aerodynamics (the study of gases) and hydrodynamics (the study of liquids).
		For flow of gases, to determine whether to use compressible or incompressible fluid dynamics, the Mach number of the problem is evaluated.
	en.wikipedia.org /wiki/Fluid_dynamics (1458 words)

	Strouhal number
		In dimensional analysis, the Strouhal number is a quantity describing oscillating flow mechanisms.
		where Sr is the Strouhal number, f is the frequency of vortex shedding, D is the hydraulic diameter of the object in the fluid flow and V is the velocity of the fluid.
		The Strouhal number is a function of the Reynolds number Re and in the region 200
	www.ebroadcast.com.au /lookup/encyclopedia/st/Strouhal_number.html (82 words)

	Journal of the Brazilian Society of Mechanical Sciences and Engineering - Vorticity shedding and acoustic resonance in ... (Site not responding. Last check: 2007-11-03)
		Strouhal number design charts for vortex shedding in tube bundles are presented for a wide range of tube patterns and spacing ratios.
		It corresponds to a Strouhal number of 0.4.
		The Strouhal numbers of the main components of vortex shedding in normal triangle arrays are given in Fig.
	www.scielo.br /scielo.php?script=sci_arttext&pid=S1678-58782006000200008 (8690 words)

	Learn more about Fluid mechanics in the online encyclopedia. (Site not responding. Last check: 2007-11-03)
		The foundational axioms of fluid mechanics are the conservation laws, specifically, conservation of mass, conservation of momentum (also known as Newton's second law), and conservation of energy These are based on classical mechanics and are violated in relativistic mechanics.
		In order to determine whether to use compressible or incompressible fluid mechanics, the Mach number of the problem is evaluated.
		Turbulence is instead modeled using one of a number of turbulence models and coupled with a flow solver that assumes laminar flow outside a turbulent region.
	www.onlineencyclopedia.org /f/fl/fluid_mechanics_1.html (961 words)

	Strouhal number (Site not responding. Last check: 2007-11-03)
		The Strouhal number St is a function of the Reynolds number Re (although a sufficiently varying one that it may be said that it is typically equal to 0.2, e.g.
		It is used in the momentum transfer in general, and in both Von Karmann vortex streets and unsteady flow calculations in particular.
		Strouhal number as a function of the Reynolds number
	enseeiht.fr /hmf/travaux/CD0102/travaux/optmfn/gpfmho/01-02/grp6/pages/strouhal.htm (127 words)

	Fluid dynamics (Site not responding. Last check: 2007-11-03)
		The foundational axioms of fluid dynamics are the conservationlaws, specifically, conservation of mass, conservationof momentum, (also known as Newton's second law orthe balance law), and conservation of energy.
		The Reynolds number can be used to evaluate whether viscous or inviscid equations are appropriateto the problem.
		Turbulence is instead modeled using one of a number of turbulence models and coupledwith a flow solver that assumes laminar flow outside a turbulent region.
	www.therfcc.org /fluid-dynamics-59.html (858 words)

	style.org > The Strouhal Number in Cruising Flight
		This dimensionless ratio is the Strouhal number, and evolution seems to favor efficient swimming motion with a Strouhal number in the range of 0.2–0.4.
		In particular, although the authors of the Nature article provide a chart of Strouhal numbers for flapping flight and swimming along with their statistical analysis, I wanted to see what ratios of amplitude, frequency, and speed actually look like in winged flight, what the Strouhal number actually represents, and why it is dimensionless.
		and the kestral’s Strouhal number (St) of.235 is represented by the slope (St=y/x).
	www.style.org /strouhalflight (1501 words)

	MKleinResearch97 (Site not responding. Last check: 2007-11-03)
		Reduced peak frequency, in the form of Strouhal number, has been shown to scale with freestream velocity and model scale.
		Strouhal number is defined as peak frequency times model length scale divided by velocity.
		A nearly constant Strouhal number is seen through three orders of magnitude of Reynolds number and multiple model scales, to full scale flight tests.
	www.adl.gatech.edu /f15tail/F15Strouhal.html (151 words)

	B.T. TAN --- Results
		A plot of the predicted vortex shedding Strouhal numbers, together with results of previous studies, showing the stepwise increase is shown in Figure 4.
		The different Strouhal number steps shown in Figure 4 represent different modes of shedding and are conjectured to result from a feedback loop.
		It is not surprising then that Figure 8, a plot of the Strouhal number based on chord corresponding to a local maximum in base suction as a function of c/t, shows a stepwise increase.
	www.mae.cornell.edu /IJFD/1998_vol2/paper1/Tan.Results.html (2220 words)

	Direct Numerical Simulation of Pulsed Jets in Cross-Flow
		In the course of this work, a range of Strouhal numbers (.025,.05,.1,.2,.4,.6,.8, and 1) were examined for sine, square, and spiked waveforms on the coarsest grid.
		As dramatic changes in the mixing, spreading, and penetration of the jet were observed at Strouhal numbers of.2,.4, and.6 for the sine wave forms, a DNS is performed for these cases along with the unpulsed case.
		In this study, pulsing at a Strouhal number of.4 causes the jet to split into three vertical jets and to penetrate much further, while a Strouhal number of.6 causes the jet to split into two horizontal jets and to remain much closer to the jet exit (see Figure 2).
	www.navo.hpc.mil /Navigator/sp04_Feature3.html (1016 words)

	A. Hirschberg, M.P. Verge: Turbulence Noise in Flue Instruments (ISMA 95, Dourdan, 1995). Médiathèque de l'Ircam © ...
		The Reynolds number is therefore high enough for the jet to develop into turbulence but only after a certain delay or having interacted with the edge of the labium.
		The calculated noise sources display a maximum amplitude for values of the Strouhal number shifting from approximately 0.08 to 0.03 as the blowing pressure is increased.
		For this range of Reynolds number, the scaling of the source amplitude with the jet velocity could not be clearly established because of a lack of experimental data at low driving pressures.
	mediatheque.ircam.fr /articles/textes/Hirschberg95a (2558 words)

	ISAS Official Publications
		The variation of the Strouhal number with the number of cylinders or the number of rows is shown in Fig.
		In the case of the single row arrangement (OOO1-R, O002-R, O003-R and O004-R), the Strouhal number increases with the increase in the number of cylinders, since the flow through the cylinders is accelerated by increasing the blockage ratio and the rise in the local flow velocity results in more frequent vortex shedding in the wake.
		In the case that there are four cylinders in a row (0004-R, 0044-R, 0444-R and 4444-R), the Strouhal number decreases with the increase in the number of rows, since the velocity loss in the cylinder array becomes significant.
	www.isas.ac.jp /publications/report/676/67609.html (1010 words)

	Effects of Formation Number on (Site not responding. Last check: 2007-11-03)
		One of the variables in the Strouhal number is the frequency f.
		The Strouhal number is kept constant for each run while the pulse width is varied such as to make it either 1/2, 1/3, 1/4, or 1/5 of the period between consecutive pulses.
		Keeping the Strouhal number constant, pulse width varied from 1/3 to 1/5 of the period between the pulses.
	www-mcnair.berkeley.edu /98journal/gacevedobolton (2649 words)

	vortex Flowmeters
		Where St is the Strouhal number, f is the vortex shedding frequency, d is the width of the bluff body, and V is the average fluid velocity.
		The value of the Strouhal number is determined experimentally, and is generally found to be constant over a wide range of Reynolds numbers.
		The Strouhal number is a dimensionless calibration factor used to characterize various bluff bodies.
	saba.kntu.ac.ir /eecd/Ecourses/instrumentation/projects/reports/Flowmeter/vortex.htm (2515 words)

	eFunda: Introduction to Vortex Flowmeters
		The frequency of vortex shedding is definite and is related to the Reynolds number (flow velocity, viscosity of fluid, and the diameter of the cylinder).
		The frequency of vortex shedding is the same as the vibrating frequency of the cylinder induced by the flow.
		The Strouhal number is a dependent variable of the Reynolds number:
	www.efunda.com /DesignStandards/sensors/flowmeters/flowmeter_vtx.cfm (555 words)

	Magic number revealed for flying and swimming - 15 October 2003 - New Scientist
		A single magic number describes the locomotion of flying and swimming animals, from moths to dolphins.
		A simple number called the Strouhal number describes locomotion produced by the flapping of wings.
		It turned out that the Strouhal number for almost all these animals once again fell in the 0.2 to 0.4 range.
	www.newscientist.com /article.ns?id=dn4280 (464 words)

	Sn-Sz
		The purpose was to examine the response of the atmospheric and oceanic boundary layers to the passage of storms.
		A dimensionless number or parameter proportional to the reciprocal of vortex spacing.
		It is expressed as a number of obstacle parameters and generally used in momentum transfer calculations, e.g.
	stommel.tamu.edu /~baum/paleo/ocean/node36.html (10857 words)

	Strouhal numbers and optimization of swimming by odontocete cetaceans -- Rohr and Fish 207 (10): 1633 -- Journal of ...
		Strouhal numbers and optimization of swimming by odontocete cetaceans -- Rohr and Fish 207 (10): 1633 -- Journal of Experimental Biology
		The cetacean Strouhal number data of Triantafyllou et al.
		Histogram of percentage of delphinid cetacean Strouhal number (St) data (n=248); incremental St range is 0.1, incremental step is 0.25.
	jeb.biologists.org /cgi/content/full/207/10/1633 (4490 words)

	[convergent evolution ~ common Strouhal number] - A New Kind of Science: The NKS Forum (Site not responding. Last check: 2007-11-03)
		My hope was that they might be similar to the 0.2-0.4 range shown for birds, bats and insects, but for cyclists the Strouhal numbers I've calculated are about a factor of 10 smaller: about 0.035-0.048 (using cadence in RPMs X (2Xcranklength)/velocity.
		I'm not sure these numbers are particularly significant if they aren't comparable to bird Strouhal numbers, especially since the mechanical factors to consider are quite different.
		In any event, it may be that the Strouhal numbers I have found arise in other situations or animal species.
	forum.wolframscience.com /archive/topic/296-1.html (306 words)

	style.org > Estimating the Airspeed Velocity of an Unladen Swallow
		With those two numbers, it will be possible to estimate airspeed (U).
		By inverting this midpoint Strouhal ratio of 0.3 (fA/U ≈ 0.3), Graham K. Taylor et al.
		The maximum speed the birds could maintain was 13–14 meters per second, and although the Lund study does not discuss cruising flight in particular, the most efficient flapping (7 beats per second) occurred at an airspeed in the range of 8–11 meters per second, with an amplitude of 90–100° (17–19 cm).
	www.style.org /unladenswallow (1050 words)

	Strouhal Numbers (Site not responding. Last check: 2007-11-03)
		Dedicated to the scientific method, free markets, deflating ballyhoo, creating value, and laughter; a forum for us to use our meager abilities to make the world of specinvestments a better place.
		Abstract: "By immersing a compliant yet self-supporting sheet into flowing water, we study a heavy, streamlined, and elastic body interacting with a fluid.
		We find that above a critical flow velocity a sheet aligned with the flow begins to flap with a Strouhal frequency consistent with animal locomotion.
	www.dailyspeculations.com /ryan/strouhal.html (224 words)

	[No title] (Site not responding. Last check: 2007-11-03)
		The Strouhal number is a non-dimensional parameter that is a function of the Reynolds number.
		If the proper units are chosen, the Reynolds number is a non-dimensional number that is proportional to the ratio of inertial force to viscous force acting on an object.
		However, as the Reynolds number is increased above ~105, the deviation of the Strouhal number from 0.2 also becomes greater.
	www-personal.engin.umich.edu /~eugenew/lab7/Background.doc (1580 words)

	Strouhal Number
		An introduction to and a definition of the Strouhal Number
		The Strouhal Number is a dimensionless value useful for analyzing oscillating, unsteady fluid flow dynamics problems.
		The Strouhal Number represents a measure of the ratio of inertial forces due to the unsteadiness of the flow or local acceleration to the inertial forces due to changes in velocity from one point to an other in the flow field.
	www.engineeringtoolbox.com /strouhal-number-d_582.html (284 words)

	Strouhal Number (Site not responding. Last check: 2007-11-03)
		Strouhal number is proportional to the reciprocal of vortex spacing expressed as no. of obstacle diameters and is used in momentum transfer in general and Van Karman vortex streets and unsteady state flow calculations in particular.
		It is normally defined in the following form :
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	www.processassociates.com /process/dimen/dn_str.htm (56 words)

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