Designation:D6011−96(Reapproved2015)StandardTestMethodforDeterminingthePerformanceofaSonicAnemometer/Thermometer1ThisstandardisissuedunderthefixeddesignationD6011;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofthedy-namicperformanceofasonicanemometer/thermometerwhichemploystheinversetimemeasurementtechniqueforvelocityorspeedofsound,orboth.Performancecriteriainclude:(a)acceptanceangle,(b)acousticpathlength,(c)systemdelay,(d)systemdelaymismatch,(e)thermalstabilityrange,(f)shadowcorrection,(g)velocitycalibrationrange,and(h)velocityresolution.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2C384TestMethodforImpedanceandAbsorptionofAcous-ticalMaterialsbyImpedanceTubeMethodD1356TerminologyRelatingtoSamplingandAnalysisofAtmospheresD5527PracticesforMeasuringSurfaceWindandTempera-turebyAcousticMeansIEEE/ASTMSI10AmericanNationalStandardforMetricPractice3.Terminology3.1Definitions—Fordefinitionsoftermsrelatedtothistestmethod,refertoTerminologyD1356.3.2DefinitionsofTermsSpecifictoThisStandard:3.2.1axialattenuationcoeffıcient—aratioofthefreestreamwindvelocity(asdefinedinawindtunnel)tovelocityalonganacousticpropagationpath(vt/vd)(1).33.2.2criticalReynoldsnumber(Rc)—theReynoldsnumberatwhichanabruptdecreaseinanobject’sdragcoefficientoccurs(2).3.2.2.1Discussion—ThetransducershadowcorrectionsarenolongervalidabovethecriticalReynoldsnumberduetoadiscontinuityintheaxialattenuationcoefficient.3.2...
