简介:Turbiditycurrentsareflowsdrivenbysuspendedsedimentofflood-inducedturbidriverwaterwithexcessdensity.Suchcurrentsareoftenthegoverningfactorinreservoirsedimentationbytransportingfinematerialsoverlongdistancesanddeliveringthemajorityofdeposition,whichthusreducesthestoragecapacity.Therefore,thedesignandoperationofareservoirrequiresanaccuratepredictionofitsoccurrenceconditionandplungingposition,whichistheobjectiveofthepresentstudy.Thisarticlepresentsaverifiedalgebraicslipmixturemodelincludingmomentum,continuityandalgebraicvelocityexpressionstosimulate2-Dturbiditycurrents.Testexperimentsinamultiphaseflumewerecarriedout.Reynoldsnumber,sedimentconcentrationanddensimetricFroudenumberwereusedasparametersintheoccurrenceconditionanalysis.Theplungingofturbiditycurrentsmayproducerefluxandbackflowduetothedivingflowatthesurfaceoftheclearwater.ThesimilarexperimentalresultswerealsoobtainedbyPIVmeasurements
简介:Onthebasisofroughsettheory,thestrengthsofdynamicreductionareelaboratedcomparedwithtraditionalnon-dynamicmethods.Asystematicconceptofdynamicreductionfromsamplingprocesstothegenerationofthereductsetispresented.Anewmethodofsamplingiscreatedtoavoidthedefectsofbeingtoosubjective.Andinordertodealwiththeover-sizedtimeconsumingproblemintraditionaldynamicreductionprocess,aquickalgorithmisproposedwithintheconstraintconditions.Wehavealsoprovedthatdynamiccorepossessestheessentialcharacteristicsofareductioncoreonthebasisoftheformalizeddefinitionofthemulti-layereddynamiccore.
简介:ACHARACTERISTICANALYSISOFAEROSOLSFROMSANDSTORMSYangDongzhen(杨东贞),WangChao(王超)andYuXiaolan(于晓岚)InstituteofAtmosphericChenmistr...
简介:Thispaperinvestigatestheswimmingperformanceoffishundulatorymotionwhichisthebasicforminlocomotionofaquaticalanimalfromahydrodynamicspointofview.Inparticular,thepropulsivecharacteristicsisdiscussed.Thethree-dimensionalpotentialflowoveramodelrectangularflexibleplateperformingthemotionwhichconsistsofaprogressivewaveofagivenwavelengthandphasevelocityalongthechordistreated.Vortexringmethodisusedtocalculatethethrust,thepowerrequiredandthehydrodynamicpropulsiveefficiency,etc.Thedependenceoftheseenergeticsoncertainphysicalparameters,suchastheaspectratio,thereducedfrequencyandthewavenumber,isdiscussed.Itisfoundthatasthewavetengthgetsclosetothebodylength,propulsiveperformanceisnolongersensitivetotheaspectratio.Somequalitativeexplanationofthefishswimmingphenomenaisalsogiven.
简介:<正>ThetruncationequationforthederivativenonlinearSchrodingerequationhasbeendis-cussedinthispaper.TheexistenceofaspecialheteroclinicorbithasbeenfoundbyusinggeometricalsingularperturbationtheorytogetherwithMelnikov’stechnique.
简介:Derechos经常发生在欧洲和美国,而是在中国的derechos的报告是少见的。在这份报纸,雷达,卫星,和表面观察,数据被用来在2011年4月17日在华南分析一个derecho事件。对流系统与中等对流可得到的精力在环境形成了的生产derechomesoscale,大垂直的风砍,并且在中间的对流层的干燥的层,并且进行与前面和一根表面风集中线一起向南方。暴风能在雷达回响的特征和强风的原因根据差别被划分成二个阶段。一个阶段是一个supercell阶段,有塑造鞠躬的雷达回响的高降水的supercell的下沉后面的流入在导致了FujitaF0班强风。另外的阶段是一个non-supercell阶段(回响是顺序肾形的,塑造脚,并且一个平常的单个房间),在哪个downbursts在FujitaF1班上导致了强风。这个derecho事件有许多类似,derechos在西方的国家观察了。例如,暴风对吝啬的流动垂直,强风位于鞠躬回响的鼓起的部分,并且derecho移动了与表面前面一起向南方。一些差别也被观察。摘要规模的强迫当进展不在时是弱的高振幅的midlevel马槽并且伴随强壮的表面气旋;然而,垂直的风砍是很强壮的,典型地代表与强壮的摘要规模的强迫联系的derechos的一个特征。对流可得到的势能以前被认为必要到弱强迫的原型和混合derechos的形成的对流可得到的势能和downdraft的极其高的价值;然而,这些价值多不到2000J在这个derecho事件期间。