Two-dimensionalsimulationofdropdeformationandbreakupataroundthecriticalWebernumberOriginalResearchArticle

Thebreakupoftwo-dimensionalliquiddropsisnumericallyinvestigatedataroundthecriticalWebernumber.TheMovingParticleSemi-implicit(MPS)methodisusedtosolvetheunsteadyNavier–Stokesequationsforboththedropsandtheambientfluid.Thetwodominantforcesaffectingdropbreakup,pressuredragandsurfacetensionforce,areverifiedusingthetwobenchmarks:pressuredistributiononthesurfaceofacylinderinauniformflowandoscillationofasquaredropundersurfacetensionforce.Theresultsshowthatthebreakupprocessoccursintwostages.Duringthefirststage,thedropsbecomestretchedandthinnednormaltotheflowdirectionoftheambientfluid.Duringthesecondstage,detachedpointsappearonthesurfaceofthedrops,whichareascribedtotheunstablegrowthofsurfacewaves.Thepost-breakuptopologyofthedropsisdependentonthevalueoftheWebernumber:thelargertheWebernumberis,themoredetachedpointsonthesurfaceofthedropsemerge.Anotherfeaturecommonlysharedinthetwostagesisthatsomefinefragmentationsarestrippedfromtheequatorialedgesofthedrops.ThecriticalWebernumberispredictedtobe13foruraniumdioxidedropsinwater,atwhichbreakupregimeisconsistentwiththeso-calledvibrationregime.