Thrust producing mechanisms in ray-inspired underwater vehicle propulsion

(整期优先)网络出版时间:2015-01-11
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Thispaperdescribesacomputationalstudyofthehydrodynamicsofaray-inspiredunderwatervehicleconductedconcurrentlywithexperimentalmeasurements.High-resolutionstereo-videosofthevehicle’sfinmotionsduringsteadyswimmingareobtainedandusedasafoundationfordevelopingahighfidelitygeometricalmodeloftheoscillatoryfin.ACartesiangridbasedimmersedboundarysolverisusedtoexaminetheflowfieldsproducedduetothesecomplexartificialpectoralfinkinematics.SimulationsarecarriedoutatasmallerReynoldsnumberinordertoexaminethehydrodynamicperformanceandunderstandtheresultantwaketopology.Resultsshowthatthevehicle’sfinsexperiencelargespanwiseinflexionofthedistalpartaswellasmoderatechordwisepitchingduringtheoscillatorymotion.Mostthrustforceisgeneratedbythedistalpartofthefin,anditishighlycorrelatedwiththespanwiseinflexion.Twosetsofinter-connectedvortexringsareobservedinthewakerightbehindeachfin.Thosevortexringsinducestrongbackwardflowjetswhicharemainlyresponsibleforthefinthrustgeneration.