简介：AChebyshevfittingwayforapropelleratlasacrossfourquadrantsisdiscussed.Asanexample,Chebyshevpolynomialfittingresultsanditserroranalysisaregiven.Becauseit’sdifficultgenerallytogetapropelleratlasacrossfourquadrants,awayisusedtoconstructanalternativewithhigheraccuracybasedontheproperties.Asanapplicationexample,analternativeforthepropellerpropertyofaDeepSubmergenceVebicleacrossfourquadrantsisgivenpracticallyandasimulationmodelofthe

简介：Thehydrodynamicanalysisofmulti-floatingbodiesisimportantandwidelyusedinmarineengineering.Inthisstudy,wesystematicallysimulatedthewavediffractionproblemofafixedverticalfour-cylinderstructureinregularwavesinthetimedomaininaviscousnumericalwavetank.Thehydrodynamicinteractionofwaveswithabottom-mountedstructureconsistingoffourverticalcylindersarrangedatthecornersofasquareshowsacomplicatedinterferencephenomenon.Inthispaper,weillustrateandanalyzetherun-uparoundthestructureandthecorrespondingwaveforces.Toinvestigatetheviscouseffectonthenear-trappingphenomenon,wepayparticularattentiontoinvestigatingthewavesnear-trappedinsidethefour-cylinderstructure,andmakeacomparativestudyoftheviscous-andinviscid-flowsolutionswiththeexperimentalmeasurements.Theresultsshowthatthemaximumwaveelevationoccursontheinnersideoftheleesidecylinder,andthatthewaveelevationsontheoutersideofthecylindersarelowerthanthoseontheinnerside.Wecanconcludethatviscosityhasanobviousdampingeffectonwaveelevationsinsidethestructure.Thecylindersshowatendencytodriftapartfromeachotherwhenthenear-trappingphenomenonoccurs.