简介：Numericalanalysisofthree-dimensionalsoundpropagationinsoft-softorsoft-hardcircularductswithcircumferentialandaxialmodesofsoundsourcesattheinlethasbeencarriedout.Inthispaper,thenumericalmethodandthesamplesareofferedandtheeffectsofcircumferentialandaxialmodesonnumericalresultsarediscussedindetail.

简介：Thefinite-dmerencetime-domam（FDTD）methodisproposedforanalyzingthesurfaceacousticwave（SAW）propagationintwo-dimensional（2D）piezoelectricphononiccrystals（PCs）atradiofrequency（RF）,andalsoexperimentsareestabhshedtodemonstrateitsanalysisresultofthePCs’bandgaps.TheFDTDmethodtakesthepiezoelectriceffectofPCsintoaccount,inwhichperiodicboundaryconditionsareusedtodecreasememory/timeconsumptionandtheperfectlymatchedlayerboundaryconditionsareadoptedastheSAWabsorberstoattenuateartificialreflections.TwoSAWdelaylinesareestabhshedwith/withoutpiezoelectricPCslocatedbetweeninterdigitaltransducers.Byremovingseveralechoeswithwindowgatingfunctionintimedomain,delaylinestransmissionfunctionisachieved.ThePCs’transmissionfunctionsandbandgapsareobtainedbycomparingtheminthesetwodelaylines.WhenAluminum/128°YX-LiNbO3isadoptedasscatterandsubstratematerial,thePCs’bandgapiscalculatedbythisFDTDmethodandCOMSOLrespectively.ResultsshowthatcomputationalresultsofFDTDagreewellwithexperimentalresultsandarebetterthanthatofCOMSOL.

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简介：Usingthetimereversal(TR)-reversetimemigration(RTM)mixedmethod,thenumericalanalysistowardstheacousticfieldfordetectionandlocationoftargetsinlayeredmediaisperformed.Firsttheapproachesandstepsofthenumericalanalysisandsimulationforacousticfieldareproposed,then,theacousticfielddistributionofsingletargetandmultipletargetsarefurthercomputedbyusingtheapproachesofsingleemission-multiplereceivingandmultipleemission-multiplereceiving.Thenumericalsimulationresultsindicatethattargetdetectionandlocationcanbewellrealized.Bycomparison,goodresultsareobtainedfromthebothtwoapproaches,butlargetime-consumingisobservedinwayofmultipleemission-multiplereceiving,andsowouldbeunacceptable.Additionally,theimprovedwayisalsoproposedformultipletargetdetection.