简介:Thecalculationaccuracyofthesuspendedsedimenttransportratereliesonthatoftheverticaldistributionoftheparticleconcentration,theparticlevelocitydistributionandthereferenceconcentration.Inviewofthelimitationsoftheprevionsformulasforboththevelocityandtheconcentrationdistributions,generalexpressionsareintroducedtothecalculationofsus-pendedsedimenttransportrate.Basedontheseanalyses,asimpleandpracticalcalculationmodelisgiveninthepresentpaper.
简介:Inthispaperthecomplexstructureandpatternofshipsternflowdrivenbymulti-propellersissimulatednumericallybyusingRANSequationswithK-εturbulencemodelandpropellerliftingsurfacetheoryasessentialresearchtoolandcouplingthecomputercodeofshipsternflowtothecomputercodeofpropellerperformancepredictionthroughthemediumofbodyforce.Ashipmodelwithfourpropellersisselectedasthenumericalexample.Detailedcomputationalresultsarepresentedgraphicallyandthequalitativeandquantitativeanalysisismade.Finally,thecomparisonbetweenthecalculatedresultandtheavailableexperimentaldataismade.Theagreementbetweenthemissatisfactory.
简介:Thewaterintakeheadinstalledwithinclinedboardingsiscalledlaminatesedimentprecipitation,whichseparatesliquidandsolidparticlesintwo-phaseflowbygravity.ThepaperpresentstheequationsforcalculatingthedistanceHbetweentwoincllinedboardings,indicatingthatHhasakeyeffectontheparticleprecipitationvelocityV2.Thepaperfocusesalsoonthecal-culationofhydraulicsimilarityofmodelwiththetheoreticmodel.
简介:Themeasurementaccuracyofanultrasonicheatmeterdependsontherelationshipoftheprofile-linearaveragevelocity.Therearevariousmethodsforthecalculationofthelaminarandturbulenceflowregions,butfewmethodsforthetransitionregion.Atpresent,thetraditionalmethodtodealwiththetransitionregionistoadopttherelationshipfortheturbulentflowregion.Inthisarticle,asimplifiedmodelofthepipeisusedtostudythecharacteristicsofthetransitionflowwithspecificReynoldsnumber.Thek-εmodelandtheLargeEddySimulation(LES)modelare,respectively,usedtocalculatetheflowfieldofthetransitionregion,andacomparisonwiththeexperimentresultsshowsthattheLESmodelismoreeffectivethanthek-εmodel,itisalsoshownthattherewillbealargeerroriftherelationshipbasedontheturbulenceflowisusedtocalculatetheprofile-linearaveragevelocityrelationshipofthetransitionflow.Theprofile-linearaveragevelocityfortheReynoldsnumberrangingfrom5300to10000arecalculated,andtherelationshipcurveisobtained.Theresultsofthisarticlecanbeusedtoimprovethemeasurementaccuracyofultrasonicheatmeterandprovideatheoreticalbasisfortheresearchofthewholetransitionflow.
简介:Thepurposeofthispaperistofindsomebettermethodsforcalculatingin-lineforcesonaverticalcircularcylinderandforanalysingthehydrodynamiccoefficientsC_DandC_Minwave-currentco-existingfield.Inthispa-per,inordertocalculatehydrodynamicforces,theauthorstrytofindawayofapplyingagreatnumberofthere-sultsaboutC_DandC_Mforwave-onlyfieldinthecaseofwave-currentco-existingfield,andtheresultsaboutC_DandC_Mobtainedinregularwavesintheeaseofirregularwaves.Suchawaymaybeofsignificanceinengineeringandfurtherresearch.