简介:ByusingtheReynoldsStressClosureModel(RSM),turbulentCounter-Gradient-Transport(CGT)phenomenonwasnumericallyinvestigatedinasymmetricflowwithajet,andthecomputationalresultswerecomparedwithexperimentaldata.ThecomputationalresultsshowthatthenegativeturbulentenergyproductiononlyappearsatsomecertainstationsinCGTregion,thisfactindicatesthattheCGTphenomenonexistsmorewidelythanthenegativeturbulentenergyproduction;whiletheCGTregionexistsallalong,itgraduallyshrinksinthefavorablepressuregradientzoneuntilthepositionofthewingcentralpartisreached,whereitvanishes,butitappearsintheadversepressuregradientregion;inaddition,thelocationintheflowwhereuv=0switchedsides,relativetowhere()U/()y=0,fromfavorablepressuregradienttoadversepressuregradient.ThepressuregradienttakesanimportanteffectontheregionofnegativeturbulentenergyproductionandCGT.
简介:Duringthedevelopmentoflowpermeabilityreservoirs.theinteractionbetweenfluidflowandrock-massdeformationisobvious.Onthebasisoffluidmechanicsinporousmediaandelasto-plastictheory.theauthorpresentsanequivalentcontinuummodeltosimulatefluidflowinfracturedlow-permeabilityoilreservoircoupledwithgeo-stress.Themodelnotonlyreflectstheporositychangeofmatrix,butalsothepermeabilitychangeduetotheopeningandclosingoffracture.Byanalyzingofsimulationresults,thechangesinporosityandpermeabilityandtheireffectonoildevelopmentarestudied.
简介:AraisedpanelmethodbasedonNURBS(Non-UniformRationalB-Splines)forfree-surfaceflowswithforwardspeedispresented.Inthisgeneralizedpanelmethod,NURBSareemployedtorepresentthebodygeometry,disturbedfreesurface,andtoexpresstheunknownsourcestrengthdistribution,onthebodysurfaceandabovethefreesurface.Comparedwithcommonhigher-orderpanelmethods,ithasnoneedofadoptinglocalcoordinates.NURBSmakethegeometryrepresentationofthebodyshapeandthewavepatternmoreprecise.Raisedpanelsabovethefreesurfaceproducelessnumericaldispersionerror,needlessCPUconsumptionandarehelpfulandcombinedwithcollocation-pointshiftingup-stream,cansatisfytheradiationconditionnumerically.ByusingcontinuousanddiscreteFourieranalysis,numericalerrorsofthismethodarediscussedandageneralexpressionfortheerrorsofnumericaldampinganddispersion,includingtheeffectsoftheverticaldistanceofsingularitiestothefreesurface,theorderofsingularitydistributionrepresentedbyB-splinesinpanels,andcollocation-pointshiftingisderived.