Numerical Study of the Secondary Circulations in Rip Current Systems

(整期优先)网络出版时间:2015-01-11
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Toinvestigatethemechanismofsecondarycirculationsinripcurrentsystems,andtoexploretherelationshipbetweenwaveconditionsandsecondarycirculationintensity,aseriesofnumericalexperimentsisperformedusingcouplednearshorewavemodelandcirculationmodel.Intheseexperiments,theripcurrentsandsecondarycirculationsgeneratedabovebarredbeacheswithripchannelsaresimulated.Acomparisonexperimentisconductedtoinvestigatetheformationandhydrodynamicsofthesecondarycirculations.Modelresultsindicatethatthesecondarycirculationsconsistofalongshoreflowsdrivenbywaveset-upneartheshoreline,partofthefeedercurrentsdrivenbythewaveset-upoverthebars,andonshoreflowsattheendoftheripchanneldrivenbywavebreakingandconvection.Theexistenceofthesecondarycirculationbarelyaffectstheripcurrent,butnarrowsandintensifiesthefeedercurrents.Threegroupsofexperimentsofvaryingincidentwaveconditionsareperformedtoinvestigatetherelationshipbetweenwaveconditionsandsecondarycirculationintensity.Thevelocityofthealongshoreflowofthesecondarycirculationissensitivetothevariationoftheincidentwaveheightandwaterdepth.Itisalsofoundthatthealongshoreflowintensityisindirectproportiontothealongshorevariationofthewaveheightgradientbetweenthebarsandtheshoreline.