简介:Thispaperisconcernedwiththewavesgeneratedbya3-Dbodyadvancingbeneaththefreesurfacewithconstantspeedinatwo-layerfluidoffinitedepth.ByapplyingGreen'stheorem,alayeredintegralequationsystembasedontheRankinesourcefortheperturbedvelocitypotentialgeneratedbythemovingbodywasderivedwiththepotentialflowtheory.Afour-nodeisoparametricelementmethodwasusedtotreatwiththesolutionofthelayeredintegralequationsystem.Thesurfaceandinterfacewavesgeneratedbyamovingballwerecalculatednumerically.Theresultswerecomparedwiththeanalyticalresultsforamovingsourcewithconstantvelocity.
简介:Twonear-fieldmethods,namelytheintegralmethodanddifferentialmethod,werepresentedforgivingsecond-ordermeandriftforcesandmomentsbetweentwofixedsubmergedbodiesinregularwaves.Fortheintegralmethod,withaseriesofmathematicalmanipulations,second-orderdriftforcesandmomentscouldbeeasilyexpressedbydistributedsourceswhichcouldbecalculatedbysourcedistributiontechniqueswiththeassumptionthattheamplitudeofshipmotionsaresmallonthebasisofthelinear3Dfrequencytheory.Forthedifferentialmethod,driftforcesandmomentscouldbeexpressedbythederivativeofvelocitypotentialwithrespecttospacecoordinate.Becausetwobodieswouldbehaveasasinglebodywhiletheclearanceisverylarge,thenumericalresultsofonesphereinsuchcaseweregivenandcomparedwithanalyticalresultsofasinglespherewhichdoesnotinvolvetheeffectoffreesurface.Whensubmergeddepthbecomesenoughlarge,agoodagreementcanbereached.Thentheintegralmethodwasusedtopredictthesecond-orderdriftforcesandmomentsoftwosubmergedspheresandspheroidswithasmalllateralseparationdistanceinwavescomparedwiththenumericalresultsobtainedbythedifferentialmethodandtheyagreewell.Bycomparison,itindicatestheinteractioneffectsbetweentwosubmergedbodieshaveaprofoundinfluenceonthedriftforcesandmoments.Inthispaper,theforwardspeedeffectonsubmergedsphereswasalsoconsidered.
简介:Inthispaper,perturbationmethodandFourier-cosine-expansionmethodareusedtosolvea3-DnonlinearproblemofasupercavitatingflowinaninclinedfieldofgravityatlargeFroudenumbers.Byexpandingthevelocitypotentialintoapowerseriesofasmallparameter,theoriginal3-Dnonlinearproblemisreducedtoanumberof2-Dones.Thesolutionsofthefirstthreeordersarederivedindetailandexpressedintermsofthecompleteellipticintegralsofthefirstandsecondkinds.Thentheboundaryintegralequationmethodisappliedtogetthenumericalsolutionsforeachorder.Computationalresultsareprovidedforsupercavitatingflowspastconesundervariousflowconditions.
简介:Ageneralizedbendflowmodel,treatinga90°singlebendand60°continuousbends,wasdesignedtoquantitativelydescribe3-Dturbulencemechanismofcirculatingnot-fully-developedflowinopenchannelswithbends.The3-Dfluctuatingvelocitiesofturbulentflowweremeasuredandanalyzedwitha3-Dacoustic-Dopplervelocimeter.Formulafor3-Dturbulentintensitywasderivedusingthedimensionanalysisapproach.Expressionsofverticalturbulent-intensitydistributionswereobtainedwiththemultivariant-regressiontheory,whichagreewithexperimentdata.Distributionsofturbulentintensityandturbulentstresswerecharacterized,andtheirrelationshipswereconcluded.Inthebend-turbulent-flowcoreregion,longitudinalandlateralturbulent-intensitydistributionsarecoincidentwithlineardistribution,butinnear-wallregionarecoincidentwiththeGammadistribution.VerticalturbulentintensitydistributionsarecoincidentwiththeRayleighdistribution.Herein,itisconcludedthatthebendturbulenceisanisotropic.
简介:Three-dimensionalseepageindoublefracturedmediawasmodeledinthispaper.Thedeterminationofhydraulicconductivitytensorofrockmassisavitalproblemfortheseawaterintrusionorseawaterencroachmentandseepageoffissuredmedium.Accordingtothegeologicalandhydrogeologicalconditionsforthe2nd-stageconstructionoftheThreeGorgesProject(TGP),thephysicalandmathematicalmodelsforthegroundwatermovementthroughthe3Ddoublefracturedmediaofrockmassduringconstructionwereestablishedinthispaper.Basedondiscontinuity-controlinversetheory,somerelatedparametersofdoublefracturedmediawereinversedwithfluxbeingtheknownquantityandcalibrationofwatertabletheobjectivefunction.Synchronously,theseepagefieldoftheconstructionregionwassystematicallyanalyzedandsimulated,theresultsofwhichexhibitthatthedoublefracturedmediamodeloffracturewatercancomprehensivelyandcorrectlydescribethegeologicalandhydrogeologicalconditionsintheconstructionregion.
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简介:天生桥一级水电站C3标合同,是唯一应用FIDIC合同条款,进行国际公开性竞争招投标的土建工程项目。合同包括混凝土面板堆石坝(坝高178m,坝顶长1168m,总填筑量1800万m3)、开敞式溢洪道(总长1808m,底宽120m,开挖总量2060万m3),以及施工导流、砂石混凝土系统临时设施。由于该标工程规模大,技术条件复杂,加上授标及合同签约推迟的影响,增加了合同管理难度。由中国人民武装警察部队水电第一总队、巴西M·J公司组成的联营体———南水公司中标后,认真履行合同责任,精心组织,精心施工,确保按原标书要求实现了1998年8月蓄水,1998年底首台机发电的总目标。该电站C3标合同管理和实施是成功的
简介:Thepurposeofthispaperistofindsomebettermethodsforcalculatingin-lineforcesonaverticalcircularcylinderandforanalysingthehydrodynamiccoefficientsC_DandC_Minwave-currentco-existingfield.Inthispa-per,inordertocalculatehydrodynamicforces,theauthorstrytofindawayofapplyingagreatnumberofthere-sultsaboutC_DandC_Mforwave-onlyfieldinthecaseofwave-currentco-existingfield,andtheresultsaboutC_DandC_Mobtainedinregularwavesintheeaseofirregularwaves.Suchawaymaybeofsignificanceinengineeringandfurtherresearch.