1、Designation:D524292(Reapproved 2013)Standard Test Method forOpen-Channel Flow Measurement of Water with Thin-PlateWeirs1This standard is issued under the fixed designation D5242;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the yea
2、r of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers measurement of the volumetricflowrate of water and wastewater in channels with thin-plateweirs
3、.Information related to this test method can be found inRantz(1)2and Ackers(2).1.2 The values stated in inch-pound units are to be regardedas the standard.The SI units given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns,if any,associat
4、ed with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to WaterD2777 Practice for Determina
5、tion of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3858 Test Method for Open-Channel Flow Measurementof Water by Velocity-Area Method2.2 ISO Standards:4ISO 1438 Flow Measurement in Open Channels Using Weirsand Venturi FlumesPart 1:Thin-Plate WeirsISO 555 Liquid Flow Measu
6、rement in Open Channels,Delusion Methods for Measurement of Steady Flow-Constant Rate Injection Method3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 crestthe bottom of the overflo
7、w section or notch ofa rectangular weir.3.2.2 headthe height of a liquid above a specified point,for example,the weir crest.3.2.3 hydraulic jumpan abrupt transition from supercriti-cal flow to subcritical or tranquil flow.3.2.4 nappethe curved sheet or jet of water overfalling theweir.3.2.5 notchthe
8、 overflow section of a triangular weir or ofa rectangular weir with side contractions.3.2.6 primary instrumentthe device(in this case the weir)that creates a hydrodynamic condition that can be sensed by thesecondary instrument.3.2.7 scow floatan in-stream float for depth sensing,usually mounted on a
9、 hinged cantilever.3.2.8 secondary instrumentin this case,a device thatmeasures the depth of flow(referenced to the crest)at anappropriate location upstream of the weir plate.The secondaryinstrument may also convert the measured depth to an indi-cated flowrate.3.2.9 stilling wella small free-surface
10、 reservoir connectedthrough a constricted channel to the approach channel up-stream of the weir so that a depth(head)measurement can bemade under quiescent conditions.3.2.10 subcritical flowopen channel flow in which theaverage velocity is less than the square root of the product ofthe average depth
11、 and the acceleration due to gravity;some-times called tranquil flow.3.2.11 submergencea condition where the water level onthe downstream side of the weir is at the same or at a higherelevation than the weir crest;depending on the percent ofsubmergence the flow over the weir and hence the head-disch
12、arge relation may be altered.3.2.12 supercritical flowopen channel flow in which theaverage velocity exceeds the square root of the product of theaverage depth and the acceleration due to gravity.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibili
13、ty of Subcommittee D19.07 on Sediments,Geomorphology,and Open-Channel Flow.Current edition approved Jan.1,2013.Published January 2013.Originallyapproved in 1992.Last previous edition approved in 2007 as D5242 92(2007).DOI:10.1520/D5242-92R13.2The boldface numbers in parentheses refer to a list of re
14、ferences at the end ofthe text.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4Available from American National S
15、tandards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.13 tailwaterthe water level immediately downstreamof the weir.4.Summary of Test Method4.1 Thin-plate
16、 weirs are overflow structures of specifiedgeometries for which the volumetric flowrate is a uniquefunction of a single measured depth(head)above the weir crestor vertex,the other factors in the head-discharge relationhaving been experimentally or analytically determined asfunctions of the shape of the overflow section and approachchannel geometry.5.Significance and Use5.1 Thin-plate weirs are reliable and simple devices thathave the potential for highly accurate flow measurements.Withproper sel