NumericalsimulationsoftheflowinthedrafttubeofaFrancisturbinearecarriedoutinordertoelucidatetheeffectsoftangentialvelocityonflowstability.Influenceofthelocationofthemaximumtangentialvelocityisexploredconsideringtheequalityofthetotalenergyattheinletofthedrafttube.Itisfoundthattheamplitudeofthepressurefluctuationdecreaseswhenthelocationofthemaximumofthetangentialvelocitymovesfromthecentretothewallonthecrosssection.Thus,thestabilityoftheflowinthedrafttubeincreaseswiththemovingofthelocationofthemaximumtangentialvelocity.However,therelativehydrauliclossincreasesandtherecoverycoefficientofthedrafttubedecreasesslightly.