Thispaperaimstostudytheoscillationofasparkgeneratedsubmergedbubblelocatednearorinsideacircularaperturemadeinaflatplateusinghigh-speedvisualizationtechnique.Inthecaseofabubbleoscillatingnearanaperturetheinitialfreesurfaceofthewaterwassetatthebottomsurfaceoftheplate.Theefectsofaperturesizeandbubblefreesurfacedistanceonthebubblebehavioraswellasontheensuingdropletdynamicsareinvestigated.Itwasfoundthatthedirectionofthebubblereentrantjetwastowardstheapertureorawayfromitrespectivelywhenthenormalizedaperturesizewassmallerorgreaterthanacertaincriticalvalue.Inaddition,atoroidalvortexringwasobservedtoform,whichrotatedinwardsasitmovedawayfromtheaperture.Itwasalsofoundthatifthebubblewasinceptedatadistancesufcientlyawayfromasupercriticalsizeapertureasingledropletcouldbeproduced.Inthecaseofabubbleinitiatedinthemiddleofacircularaperturesubmergedjustbeneaththewaterfreesurface,thebubblewasfoundtotaketheshapeofanellipsoidduringitsexpansion.Thenareentrantjetwasinitiatedandpiercedthebubblefromitstopside.
