简介：Theacousticperformanceofthestructureformeasuringcavitationnoiseistheoreticallyanalysed,andtwojudgingcriteriaoftheacousticperformanceofSTW（soundtransmissionwindow）arepresentedinthispaper.OneisofimpedancematchingbetweenworkingliquidandSTW:ρ1C1=ρ2C2.Theotherisofmaximumfrequency（orminimumwavelength）ofcavitationnoisespectrum:fmax≤c/60D(orλmin/D≥60).Ifeitherofthecriteriaismetreliablemeasuredresultsofcavitationnoisewillbeobtained.Thetheoreticalresultsareverifiedthroughexperi-ments.Accordingtothecriteria,thepaperanalysestheacousticperformanceofroutinelyusedplexiglassSTW.Theresultsshowthatintheresearchofclearwatercavitationtheimpedanceratio,2.18,doesnotsatisfyρ1C1=ρ2C2,andfmax≤C/60Dhardlyholdsforactualcavitationnoisespectrum.Therefore,plexiglassSTWisnotgoodenoughforsoundtransmission.Fromthispointofview,polyethyleneisbettersoundtransmissionmaterialthanplexi-glass.

简介：Inthisarticle,anewacoustictesttechniqueusingtowedmodelwasintroducedtostudyflownoisecausedbyasurfaceship.Theprojectofmodeltestwasbeproperlydesignedforacousticsignalcollectingandwiththehelpofappropriatedataprocessingmethoddifferentkindsofacousticsourcescouldbesuccessfullyidentified.Alotofworkaboutfuidnoisecouldbecarriedonwiththetowedmodel,andthenoisecorrespondingtolowfrequencywhichisespeciallyinterestedforitslongdistanceradiatingwithsmallattenuationcouldalsobestudiedinthisway.

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简介：Thetipvortexcavitation(TVC)noiseofmarinepropellersisofinterestduetotheenvironmentalimpactsfromcommercialshipsaswellasforthesurvivabilityofnavalships.Duetocomplicatedflowandnoisefieldaroundamarinepropeller,atheoreticalapproachtotheestimationofTVCnoiseispracticallyunrealizable.Thus,estimationofprototypeTVCnoiselevelisrealizedthroughextrapolationofthemodelTVCnoiselevelmeasuredinacavitationtunnel.Inthisstudy,forthepredictionofprototypeTVCnoiselevelfromamodeltest,anovelscalinglawreflectingthephysicalbasisofTVCisderivedfromtheRayleigh-Plessetequation,theRankinevortexmodel,theliftingsurfacetheory,andotherphysicalassumptions.ModelandprototypenoisedatawereprovidedbySamsungHeavyIndustries(SHI)forverification.Inapplyingthenovelscalinglaw,similitudeofthespectraofnucleiisappliedtoassumethesamenucleidistributioninthetipvortexlineofthemodelandtheprototype.ItwasfoundthattheprototypeTVCnoiselevelpredictedbythenovelscalinglawhasbetteragreementwiththeprototypeTVCnoisemeasurementthantheprototypeTVCnoiselevelpredictedbythemodifiedITTCnoiseestimationrule.

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