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简介：On16Auguest1996theRuralEnergyDevelomentProgramme(REDP)wasinitiatedwiththeaimofimprovinglivelihoodsofruralpeopleandpressrvingtheenvironmentthroughthepromotionofruralenergysystems.TheProgrammeisrunbytheUnitedNationsDeelopmentProgrammeandHisMajesty'sGovernmentofNepal.

简介：Themechanicalenergyequationisafundamentalequationofa1-DmathematicalmodelinHydraulicsandEngineeringFluidMechanics.ThisequationforthetotalflowusedtobededucedbyextendingtheBernoulli’sequationfortheidealfluidinthestreamlinetoastreamtube,andthenrevisedbyconsideringtheviscouseffectandintegratedonthecrosssection.Thisderivationisnotrigorousandtheeffectofturbulenceisnotconsidered.Inthispaper,theenergyequationforthetotalflowisderivedbyusingtheNavier-StokesequationsinFluidMechanics,theresultsareasfollows:(1)Anewenergyequationforsteadychannelflowsofincompressiblehomogeneousliquidisobtained,whichincludesthevariationoftheturbulentkineticenergyalongthechannel,theformulaforthemechanicalenergylossofthetotalflowcanbedetermineddirectlyinthedeductionprocess.(2)Thetheoreticalsolutionofthevelocityfieldforlaminarflowsinarectangularopenchannelisobtainedandthemechanicalenergylossintheenergyequationiscalculated.ThevariationsofthecoefficientofthemechanicalenergylossagainsttheReynoldsnumberandthewidth-depthratioareobtained.(3)Theturbulentflowinarectangularopenchannelissimulatedusing3-DReynoldsaveragedequationsclosedbytheReynoldsstressmodel(RSM),andthevariationsofthecoefficientofthemechanicalenergylossagainsttheReynoldsnumberandthewidth-depthratioarediscussed.

简介：Inordertosearchforthemeasuretoincreasetheenergydissipationratioofsteppedspillways,somemaininfluencingfactorsfortheenergydissipationratioofsteppedspillways,suchasunitdischarge,damslope,heightofstepandsoon,werestudied.Theresultsshowthattheenergydissipationratiodecreaseswiththeincreaseintheunitdischargeandincreasesastheslopebecomesgentle.Theeffectsofstepheightontheenergydissipationratioarecloselyrelatedtounitdischarge.Iftheunitdischargeissmaller,thechangeofenergydissipationratiowithstepheightbecomesgreater.While,iftheunitdischargeisgreater,theinfluenceofstepheightonenergydissipationratioisverylittle.Accordingtothedistributionsoftheturbulencekineticenergyandturbulencedissipationrateobtainedbynumericalsimulation,thebasicreasonofthedecreaseofenergydissipationratiowiththeincreaseintheunitdischargewasdiscussedandsomespecificmeasurestoincreasetheenergydissipationratioweresuggested.

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简介：Byintroducingtheextremumlawofenergydissipationrateintotheinvestigationofturbulentflow,theclosureproblemforthebasicequationsisbrieflydiscussedinconnectionwithanewlysuggestedsemi-empiricalturbulentflowmodel.Asaresult,severalunknownfunctionswhichcannotbesolvedbytheexistedsemi-empiricalmodelsareobtainedinthepresentpaper.Itisshownthattheturbulentflowmodels,astheconstraintstotheextremumproblem,havedirectinfluenceonthefinalresultsoftheprimaryparameters.

简介：Thisarticleisconcernedwiththegrowthofenergyofdisturbancesinabaroclinicflowwithinafinitetimeperiod.Theimplicitdifferenceschemewasappliedtothelinearizedvorticityequation,andthedisturbanceenergywascomputedforthreekindsofverticalshears.Itturnsoutthatallthedisturbanceenergyrapidlyincreasesinitially,andduringthesucceedingperiodthereareseveralstagesofgrowthanddecayofenergyofdisturbances,andfromacertaintimeon,allthedisturbanceenergybeginstodecrease.

简介：InthesouthernpartofChina,duetotherichrainfallsandfavourablytopographicallandscape,thereisabundanthydraulicenergyresourcescontainedinthecountlesssmallstreamsandriversinthemountainousandsemi-mountainousareas.Besidesthesmallhydropowergenerationwhichtransfersthepotentialenergytotheelectricalpower,thereisothertechnologyavailabletoutilisethepotentialenergydirectlyforthewaterliftingintheirrigationanddecentraliseddo-mesticwatersupplyinthevillagelevel.Thispaperintroducesthebasicprincipleofthehydraulicramop-erationanddescribestheapplicableopportunitiesforthehydraulicram.

简介：ThispaperistryingtohighlighttheimportanceofconstructingsmallhydropowerstationasthealternativesourceofenergyforruralelectrificationinNigeriaandstressedtheneedfortheFederalGovernmentofNigeriatoprovideaclearopenpolicythatwillmakeenvironmentfavourableandsafeforlocalandforeignprivateinvestorsonsmallHydropower.

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