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1、NumericalMethodsforComputingTurbulentFlows,PartIIMilovanPericFluidDynamicsandShipTheorySectionTechnicalUniversityofHamburg-Harburg&ICCMInstituteofComputationalContinuumMechanicsGmbH,HamburgFinite-VolumeMethods,I"Thestartingpoint:conservationequationsinintegralfor
2、m:"Thesolutiondomainissubdividedintocontiguouscells(controlvolumes)byagrid..."...whichcanbestructured,block-structured(witheitheroverlappingornon-overlappingblocks),orunstructured..."Thecellscanbetetrahedra,hexahedra,orarbitrarypolyhedra...Finite-VolumeMethods,II
3、Ablock-structured,matchinggridAblock-structured,overlappinggridFinite-VolumeMethods,IIIAblock-structured,non-matchinggridFinite-VolumeMethods,IVAnunstructuredgridTetrahedraPrismsFinite-VolumeMethods,VAcross-sectionthroughagridmadeofarbitrarypolyhedraFinite-Volume
4、Methods,VI"Threelevelsofapproximationnecessary:"Integralapproximation(quadrature)"Interpolation"Differentiation(oneorderlowerthaninFD)"Themostwidelyusedintegralapproximations:"Midpointrule"Trapezoidrule(2D)"Simpsonrule(2D)Finite-VolumeMethods,VIIMidpoint-rulefori
5、ntegralapproximation:thesimplest2nd-ordermethod,applicabletoarbitraryCVs...Finite-VolumeMethods,VIII"Linearinterpolation:Higher-orderinterpolation:polynomialfitusingvariablevaluesandgradientsatneighbornodes...Finite-VolumeMethods,IX"Convectivefluxesrequirelineari
6、zation(e.g.Picard):"Cell-facevaluesareobtainedbyinterpolationfromnodalvalues;deferredcorrectioncanbeusedtosimplifytheiterativesolutionmethodwhenhigher-orderschemesareused:"Onecanalsoblenddifferentschemesbymultiplyingtheoldpartbyafactor0??????1...Finite-VolumeMeth
7、ods,X"Diffusivefluxrequiresnumericaldifferentiation:eithergradientvectororderivativeinthedirectionnormaltocellfaceisneeded..."Cell-centergradientcanbecomputedforarbitrarypolyhedralCVsusingGausstheoremandmidpointrule:Finite-VolumeMethods,XI"Thederivativeinthedirec
8、tionnormaltocellfacecanbeapproximatedasfollows(usingdeferredcorrection):Cell-centergradientcanalsobeapproximatedusingpolynomialfit,e.g.linear:Finite-VolumeMeth