简介：Amulti-functionsamplingsystemhasbeensetupinShanghaiShip&ShippingResearchInstitute(SSSRI)whereatestonthefluctuatingpressureoftwopropellermodelswerecarriedout.Thispaperdealswithastudyonthetechnicalproblemsconcerningthemeasurementandanalysistechniquesinvolvedinthetest.Thesamplingandprocessingprocedureofsignalisoneofthemajorfactorsaffectingtheac-curacyandstabilityofthepredictionoffluctuatingpressureinducedbypropeller.Integral-peri-odsampling,highenoughsamplingfrequencyandsuitableresolutionmustbekeptinsamplingandprocessing.Theprocedureofsamplingandprocessingshouldbevalidatedbystandardsignalcorrespondingtothebladefrequencyofdifferentordersincomparativetests.

简介：这研究的目的是在昆虫的前面的飞行进入物理卓见到不稳定的力量和相关机制。在前面的飞行的不稳定的力量被学习，基于有在一致流动的震荡的翻译和旋转的陪衬的一个虚拟模型问题，由解决有一个有限元素方法的二维的不可压缩的海军司烧方程。包括进展比率，击飞机的使倾向的角度，击振幅，和搭攻击的角度的振幅，典型参数的效果在力量和流动结构上被分析。

简介：Thisarticlepresentsaspectralanalysisofwaveupliftloadsonahorizontaldeck.Thewaveupliftforcespectrumontheundersideofthedeckisobtained.Itisshownthatthewaveupliftforcespectraldensitydecreaseswiththeincreaseoftherelativeclearance1/3Δh/H.Theinfluencesofdifferentincidentwaveparameters,includingtherelativewaveheight1/3H/d,therelativedeckwidth/sBLandtherelativeclearance1/3Δh/Honthedimensionlesszerothspectralmomentoftheupliftforcesarediscussed.Itisfoundthatthezerothspectralmomentoftheupliftforcesincreaseswiththeincreaseoftherelativewaveheight1/3H/d,anddecreaseswiththeincreaseoftherelativeclearance1/3Δh/H.Anewdimensionlesspredictionmodelforthezerothspectralmomentofwaveupliftloadsonthedeckisproposedandtherelationshipbetweenthewaveupliftforcesandthezerothspectralmomentoftheupliftforceareobtained.

简介：Theobjectiveofthisstudyistodealwithunsteadyforceactingonapitchingfoilinshearflowandtostudytherelationoftheforcecharacteristicswithvortexsheddingnearthefoil.Thetwo-dimensionalincompressibleNavier-Stokesequationsinthevorticityandstream-functionformulationweresolvedwiththefourth-orderessentiallycompactfinitedifferenceschemesforthespacederivativesandafourth-orderRunge-Kuttaschemeforthetimeadvancement.Theforcecharacteristicsandvortexsheddingofthepitchingfoilinshearflowswereinvestigated.Theeffectsofsometypicalfactors,includingtheincomingflowshear,theoscillatingfrequencyandamplitude,onthevortexsheddingandforcebehaviorwereanalyzedanddiscussed.

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简介：Thepurposeofthispaperistofindsomebettermethodsforcalculatingin-lineforcesonaverticalcircularcylinderandforanalysingthehydrodynamiccoefficientsC_DandC_Minwave-currentco-existingfield.Inthispa-per,inordertocalculatehydrodynamicforces,theauthorstrytofindawayofapplyingagreatnumberofthere-sultsaboutC_DandC_Mforwave-onlyfieldinthecaseofwave-currentco-existingfield,andtheresultsaboutC_DandC_Mobtainedinregularwavesintheeaseofirregularwaves.Suchawaymaybeofsignificanceinengineeringandfurtherresearch.