简介：Theflowthroughabreastwallspillwayisgreatlyaffectedbythecentripetalforceduetoadownstreamcurvedprofile.Therefore,themeanverticalpressuredistributionattheoutletsectionisnotconsistentwiththehydrostaticpressurelaw.Thisdistributioninturnaffectsthedischargecapacityofthebreastwallspillway.Thispaperexperimentallystudiestheeffectofaconvexdownstreamprofileonthemeanpressurevariationandthedischargeofabreastwallspillwaywithoutgates.Itisindicatedthattheeffectofthecurvilinearstreamlineonthemeanverticalpressurevariationissignificant.TheregressionanalysismethodisusedtodeterminethewaterheadeffectZooftheorificeopeningthroughthemeanpressurevariation.Adischargepredictionformulaofthebreastwallspillwayisobtainedunderthelimitedconditionsofalaboratoryflume.Thepredicteddischargeiscomparedtothemeasureddischarge.Agoodagreementisevidencedforthefreeorificeflowwitherrorswithin?5%,whileabigerror(20%orevenmore)isobtainedifthehydrostaticpressurelawisusedforthedeterminationofZo.