简介：Steadywatersurfaceprofileofgraduallyvariedflowcanbecalculatedusingei-therasteadyflowapproachoranunsteadyflowapproach.Thesteadyflowapproachrequiresit-erativeprocedureswhichmayhaveconvergenceproblemsunlessthestepsize1xislessthanamaximumvalue△x.Theunsteadyflowapproachbasedontheexplicitcharacteristicmethodhasastabilityproblemunless△xislessthan△x.Aseriesofnumericalexperimentswerecarriedoutandtheresultsoftwoapproachesarecompared.
简介：ThesupersonicductflowwithfixedbackpressuretostagnationpressureratioPb/P0underheatingisinvestigatedanalytically.A“FlowPatternDiagram”Whichconsistsofsixpatternzonesisdeveloped.BythisdiagramtheactualflowstateinsupersonicductflowsystemcanbedeterminedconvenientlywhenPb/Poandheatingintensityareknows.Itisimpossibleforflowwithheavyheatingtobecomesupersonic,eventhoughthepressureratioismuchsmallerthanthecriticalpressureratio,Basedontheanalogybetweenviscouseffectandheatingeffectathermaldragfactorhaseendefined.whichcanpredicttheflowpropertyvariationduetoheatingandtherelaiveimportanceofviscouseffectandheatingeffect.
简介：Experimentswereconductedtoinvestigatetheeffectofimpellergeometryandtongueshapeontheflowfieldofcrossflowfans.Threeimpellers(Ⅰ，Ⅱ，Ⅲ）havingsameouterdiameter,butdifferentradiusratioandbladeangleswereemployedfortheinvestigation.Eachimpellerwastestedwithtwotongueshapes.Flowsurveywascarriedoutforeachimpellerandtongueshapeattwoflowcoefficients.andforeachflowcoefficientatdifferentcircumferentialpositions.Theflowistwo-dimensionalalongthebladespanexceptneartheshrouds.Thetotalpressuredevelopedbytheimpellersineachcaseisfoundtobemaximumatacircumferentialpositionofaround270°.Thetotalandstaticpressuresattheinletofimpellersaremoreorlesssameregardlessofimpellerandtonguegeometry,buttheyvaryconsiderablyatexitoftheimpellers.ImpellerⅢwithtongueT2developshighertotalpressureandefficiencywhereasimpellerⅡwithtongueT2developsminimumtotalpressure.HigherdiffusionandsmallervortexsizearethereasonsforbetterperformanceofimpellerⅢwithtongueT2。
简介：Theformulaswhicharesuitabletobirefringentmediumwithsymmetricplanearederivedbymeansofphaseretardintegration.Wehaveadoptedthisconcepttotheaxisymmetricproblemsanddeducedsomeusefulformulasforthesecases.Asapracticalapplication,thestrainrateanalysisofflowinadivergingoraconvergingvesselisillustratedattheendofthispaper.
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简介：Theknowledgeofflowregimesisveryimportantinthestudyofatwo-phaseflowsystem.AnewflowregimeidentificationmethodbasedonaProbabilityDensityFunction(PDF)andaneuralnetworkisproposedinthispaper.Theinstantaneousdifferentialpressuresignalsofahorizontalflowwereacquiredwithadifferentialpressuresensor.ThecharactersofdifferentialpressuresignalsfordifferentflowregimesareanalyzedwiththePDF.Then,fourcharacteristicparametersofthePDFcurvesaredefined,thepeaknumber(K1),themaximumpeakvalue(K2),thepeakposition(K3)andthePDFvariance(K4).Thecharacteristicvectorswhichconsistofthefourcharacteristicparametersastheinputvectorstraintheneuralnetworktoclassifytheflowregimes.Experimentalresultsshowthatthisnovelmethodforidentifyingair-watertwo-phaseflowregimeshastheadvantageswithahighaccuracyandafastresponse.Theresultsclearlydemonstratethatthisnewmethodcouldprovideanaccurateidentificationofflowregimes.
简介：
简介：Thefundamentalsofcohesivepowderconsolidationandflowbehaviourusingareasonablecombinationofparticleandcontinuummechanicsareexplained.Bymeansofthemodel'stiffparticleswithsoftcontacts',theinfluenceofelastic-plasticrepulsioninparticlecontactsisdemonstrated.Withthisasthephysicalbasis,thestationaryyieldlocus,instantaneousyieldlociandconsolidationloci,flowfunctionandcompressionfunctionarepresented.Theflowpropertiesofaverycohesivetitaniananopowder(ds=200nm)areshown.Thesemodelsarausedtoevaluateshearcelltestresultsasconstitutivefunctionsforcomputeraidedapparatusdesignforreliablepowderflow.
简介：WithoutsimplifyingtheN-SequationsofGermano’s,westudytheflowinahelicalcircularpipeemployingperturbationmethod.Athirdperturbationsolutionisfullypresented.Thefirst-second-andthird-ordereffectsofcurvatureкandtorsionтonthesecondaryflowandaxialvelocityarediscussedindetail.Thefirst-ordereffectofcurvatureistoformtwocounter-rotatingcellsofthesecondaryflowandtopushthemaximurnaxialvelocitytotheouterbend.Thetwocellsarepushedtotheouterbendbythepuresecond-ordereffectofcurvature.Thecombinedhigher-order(second-,third-)effectsofcurvatureandtorsion,arefoundtobeanenlargementofthelowervortexofthesecondaryflowatexpenseoftheupperoneandaclockwiseshiftofthecentersofthesecondaryvorticesandthelocationofmaximumaxialvelocity.Whentheaxialpressuregradientissmallenoughorthetorsionissufficientlylargerthanthecurvature,thelocationofthemaximalaxialvelocityisneartheinnerbend.Theequationofthevolumefluxisobtainedfromintegratingtheperturbationsolutionsofaxialvelocity.Fromtheequationthevalidityrangeoftheperturbationsolutionsinthispapercanbeobtainedandtheconclusionthatthethreetermsoftorsionhavenoeffectonthevolumefluxcaneasilybedrawn.Whentheaxialpressuregradientislessthan22.67,thevolumefluxinahelicalpipeislargerthanthatinastraightpipe.
简介：ＡｐｐｌｉｃａｔｉｏｎｏｆｃｅｒｔａｉｎｔｙｆａｃｔｏｒｓｏｆｅａｒｔｈｑｕａｋｅｐｒｅｃｕｒｓｏｒｙａｎｏｍａｌｙｅｖｉｄｅｎｃｅｓＣＦ（Ｅ）ＺＨＡＯ－ＢＩＺＨＥＮＧ（郑兆），ＪＵＮＺＨＡＮＧ（张军）ａｎｄＭＥＩＱＩＮＧ（庆梅）Ｓｅｉｓｍｏｌｏ...
简介：Inthepaper,theturbulentdissipationisconsideredinthemodelforstudyingtheflowovermountains.Thegoverningequationisafirstorderordinarydifferentialequationderivedfromanalgebraicequationwithoutdissipationcase.Thesolutionissensitivetotheupstreamconditionofdissipation.Thedissipationnotonlyreducesthestrengthofdiscontinuitybutalsochangesthepropertiesofthegoverningequation.Inthepaper,thequalitativecharacteristicfeaturesofthegoverningequationarediscussed.Thenumericalresultswithsuperandsub-criticalcasesarealsodiscussedindetail.Theresultsshowthattheturbulentdissipationisanimportantfactorandisnotnegligible.
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