Designation:D5389−93(Reapproved2013)StandardTestMethodforOpen-ChannelFlowMeasurementbyAcousticVelocityMeterSystems1ThisstandardisissuedunderthefixeddesignationD5389;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthemeasurementofflowrateofwaterinopenchannels,streams,andclosedconduitswithafreewatersurface.1.2Thetestmethodcoverstheuseofacoustictransmissionstomeasuretheaveragewatervelocityalongalinebetweenoneormoreopposingsetsoftransducers—bythetimedifferenceorfrequencydifferencetechniques.1.3ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Specificprecau-tionarystatementsaregiveninSection6.2.ReferencedDocuments2.1ASTMStandards:2D1129TerminologyRelatingtoWaterD2777PracticeforDeterminationofPrecisionandBiasofApplicableTestMethodsofCommitteeD19onWaterD3858TestMethodforOpen-ChannelFlowMeasurementofWaterbyVelocity-AreaMethod2.2ISOStandard:3ISO6416LiquidFlowMeasurementsinOpenChannels—MeasurementofDischargebytheUltrasonic(Acoustic)Method3.Terminology3.1Definitions—Fordefinitionsoftermsusedinthistestmethod,refertoTerminologyD1129.3.2DefinitionsofTermsSpecifictoThisStandard:3.2.1acousticpath—thestraightlinebetweenthecentersoftwoacoustictransducers.3.2.2acousticpathlength—theface-to-facedistancebe-tweentransducersonanacousticpath.3.2.3acoustictransducer—adevicethatisusedtogenerateacousticsignalswhendrivenbyanelectricvoltage,andconversely,adevicethatisusedtogenerateanelectricvoltagewhenexcitedbyanacousticsignal.3.2.4acoustictraveltime—thetimerequiredforanacousticsignaltopropagatealonganacoust...
