简介：Athree-stepfiniteelementmethod(FEM)togetherwithLargeEddySimulation(LES)isap-pliedtoincompressibleturbulentflowaroundseabedpipelinesatrelativelyhighReynoldsnumbers.Bothtwo-dimensionalandthree-dimensionalnumericalsimulationiscarriedouttodeterminethethree-dimensionaleffect.Theresultsofnumericalsimulationagreequitewellwiththewaveforcesactingonpipelinemodelsmeasuredinphysicalmodeltest.

简介：Thewave-seabedinteractionissueisofgreatimportanceforthedesignoffoundationaroundmarineinfrastructures.Mostpreviousinvestigationsforsuchaproblemhavebeenlimitedtouncoupledoronewaycoupledmethodsconnectingtwoseparatedwaveandseabedsubmodelswiththecontinuityofpressuresattheseabedsurface.Inthisstudy,astronglycoupledmodelwasproposedtorealizebothwaveandseabedprocessesinasameprogramandtocalculatethewavefieldsandseabedresponsesimultaneously.Theinformationbetweenwavefieldsandseabedfieldswerestronglysharedandthusresultsinamoreprofoundinvestigationofthemechanismofthewave-seabedinteraction.Inthisletter,thewaveandseabedmodelswerevalidatedwithpreviousexperimentaltests.Then,asetofapplicationofpresentmodelwerediscussedinpredictionofthewave-inducedseabedresponse.Numericalresultsshowthewave-inducedliquefactionareaofcoupledmodelissmallerthanthatofuncoupledmodel.

简介：Three-dimensionelectronicchartdisplayinformationsystem(ECDIS)isoneofthenewdevelopingdirectionsofelectronicnavigationchart,anditsreal-timequalityisoneoftheimportantrequirements.Inthispaperthealgorithmofsimplifyingtrianglesurfaceusingedgecontraction,whichcanensurethereal-timedisplayofobjectsinseabedenvironment,wasputforward.TheoptimumcontractionpointwasdeterminedbytheLagrangematrix,sothatthealgorithmensuresthatthecontractionpointlocatesontheoriginalmodel,meanwhilemeetsthedemandsofleastdeviation.Thisalgorithmcanimprovetheplottingspeed,andpreservetheboundarycharacterbyusingthefewertrianglestosimulateobjects.

简介：Realisticsimulationofunderwatersceneisalwaysdifficultbecauseofthespecialandcomplexvisioneffectsinunderwaterspace.Seabedisanimportantpartofunderwaterenvironment.ThispaperdescribesthemethodsforseabedscenesimulationbasedonOpenGL.Itincludesconstructionoffluctuantterrainbasedontherandomsinusoidalalgorithm,simulationofseabedflickereffectbymeansofcirculartexturemappingandgenerationofturbidityeffectbyusingfogtechniques.Fortheapplicationbasedontheleadinghighlevel3Ddevelopmentenvironment-Vega,underwaterscenesimulationisstilladifficultysincethereisnomoduleforit.BasedontheanalysisofVegasoftwareandtheresearchonseabedscenesimulationmethods,aVegaextendingmodulenamed'UnderwaterSpace'wascreatedthroughdevelopingmoduleclassandextendinglynxinterface.ThemoduleclasswasdesignedthroughdevelopingDLLwritteninC++.TheLynxwasextendedthroughdevelopingkeywordconfigurefile,GUIconfigurefileandlynxplug-inDLL.TheproblemthatVegacan'tsimulateunderwaterspace,iselementarilyresolved.Theresultsshowthatthismoduleisefficient,easyusing,andtheseabedsceneimagesarevivid.

简介：BasedonBiot'sconsolidationtheory,atwo-dimensionalmodelforcomputationoftheseabedresponsetowavesispresentedwiththefiniteelementmethod.Numericalresultsfordifferentwaveconditionsareobtained,andtheeffectsofwavenon-linearityonthewave-inducedseabedresponseareexamined.Moreover,thewave-inducedmomentaryliquefactioninuniformandinhomogeneousseabedsisinvestigated.Itisshownthatthewavenon-linearityaffectsthedistributionofthewave-inducedporepressureandeffectivestresses,whiletheinfluenceofwavenon-linearityontheseabedliquefactionpotentialisnotsosignificant.

简介：Wave-inducedtransientresponseofdisplacements,effectivestressesandporepressureinsaturateseabedaresalvedbyaconsolidationfiniteelementmethod.Theinfluenceoftheresponsestothestabilityofseabedandcoastalstructuresisshownbyanimprovedslicemethodwithcirculararcslipsurface.Dynamicelasticconsolidationtheoryandlinearpermeabilitytheoryareemployedinthesolutionofseabedresponse.Theseabedcanbeconsistedoflayeredsoilwitharbitraryboundaries.Theactingwavecanberegularorirregular.Irregularwavepressureactingonthesurfaceofseabediscalculatedbylinearsuperpositionmethod.Wave-inducedexcessstressontheslipsurfaceisconsideredinthestabilityanalysis.Thespatialandtemporalvariationsofporepressureinsandyseabedcomparewellwithexperiment.Calculationsforaverticalbreakwatershowthatthesafetyfactorofseabedandstructurewilldecreaseifwave-inducedseabedresponseisconsidered.Thescopeofdecreaseismainlyre

简介：Theassessmentofthewave-inducedsoilliquefactionplaysakeyroleinthegeotechnicaldesignforoffshorefoundations.Theunderlyingshortcomingsoftheexistingmomentaryliquefactioncriteriaareidentifiedandclarifiedbymechanismanalysesandtherecentfieldobservations.Amodifiedcriterionforthewave-inducedmomentaryliquefactionofasandyseabedisgiventodescribetheverticalporepressuredistributions.Animprovedapproximationofthemomentaryliquefactiondepthisfurtherpresented.Parametricstudyoftheeffectsofthesaturationdegreeofsoilsindicatesthatthismodificationissignificantfortheevaluationofwave-inducedmomentaryliquefaction.

简介：Inestuarineandcoastalareas,theseabedisinaconstantprocessofdynamicchangeundermarineconditions.Seabedsedimenterosionandresuspensionareimportantprocessesthatsafelycontrolthegeologicalenvironment.FieldtripodobservationsconductedintheJiaozhouBayinChinaarereported,toinvestigatetheeffectsofhydrodynamicconditionsontheerosionandresuspensionprocessesoftheseabed.Theobservationalresultsshowthatthemaximumshearstresscreatedbytidalcurrentscanreach0.35N/m~2,whichishigherthanthewave-inducedshearstressduringfairweatherconditions.Aseabederosionfrequentlyoccursduringthefloodtide,whereasaseabeddepositionoccursduringebbtide.WavescanproduceabottomshearstressapproximatelyequivalenttothatinducedbycurrentswhenthelocalwindreachesForce4withaspeedof5m/s.Whenthewindreaches7m/sandthesignificantwaveheightreaches26cm,wavesplayamoresignificantrolethancurrentsinthedynamicprocessesoftheseabedsedimentresuspensionandleadtoahighvalueofturbiditythatisapproximatelytwotoeighttimeshigherthanthatinfairweather.Theseanalysesclearlyillustratethatperiodiccurrent-inducedsedimenterosionandresuspensionaredominantinfairweather,whereasepisodichighwavesareresponsibleforsignificantsedimentresuspension.AdditionalworkisneededtoestablishamorethoroughunderstandingofthemechanismsofsedimentdynamicsintheJiaozhouBay.

简介：这份报纸建议了一个新概念一能适应腿得多打滑为在高潮汐的电流期间翻新到遥远地操作的车辆(ROV)的设计在水下管道检查。为ROV的推进器驱动的推进上的唯一的信赖被在走的一只可连接的昆虫形式的一个建议低费用biomimetic答案代替打滑。这能适应的走的优点打滑是在在海床环境上放和耐力到强壮的电流的高稳定性。在不同赔偿姿势的skid附件引起了至少四，这预定的用显示出的Solidworks流动模拟的计算机模拟流动研究增加在总的来说拖，并且否定电梯在海床ROV上强迫完成一更好在高当前的条件下面调遣并且车站保留(从0.5m/s到5.0m/s)。一个图形的用户接口被设计在robot-in-the-loop在水池测试和kinematics模拟期间与用户一起交往。

简介：Anewseabedsedimentfidelitysamplerwasdevelopedanditsthermalinsulationperformancewasstudiedandanalyzed.Thetemperaturedistributionsimulationindicatedthatthesamplequalitycouldbeinsuredbyusingthisnewsampler.BasedonANSYS10,thetemperaturefiniteelementmodelofthesamplecylinderwasestablished.Accordingtothelawofconservationofenergy,theunsteadyheattransmitequationofthesamplerundersolid-liquidcouplingconditionwasderived,thenthemathematicalmodelcalculationwascarriedoutbyusingamixedfinite-elementfinite-differencemethod,andtwothermalinsulationmethodswereused.Thesimulationwascarriedoutbyusingthethicknessofthethermalinsulationlayerandheatconductivityasthevariableparametersandthetemperaturedistributionofthesamplerandrelatedinfluencingfactorswereobtained.Optimizationanalysiswasconductedusingthesimulationdataandrelatedparametersandthemagnituderangesoftheparameterswereobtainedthatcouldmeetthedesigntemperaturerequirements.Theexperimentaldataandsimulationresultsindicatedthattheresultswereingoodagreementwiththerealities,andthissamplermightbeofvalueforseabedsedimentsamplerdesignandmanufacture.

简介：灵活起床人和钢链状的起床人经常提供独特起床人解决方案今天深海的域开发。这些苗条结构，在有高速度的HP/HT内部流动的精确分析，是批评的保证人员和财产安全。在这研究，一个特殊的全球基于坐标的女性的杆模特儿被收养识别并且确定灵活、深海的钢上的内部流动和静水力学的压力的效果链状的起床人，与后者上的强调。由合并，内部流动导致了力量进模型，内部流动贡献一个新术语到有效紧张表示，这被发现。为浅水里的灵活起床人，做的内部流动和静水力学的压力不几乎由仅仅改变起床人墙紧张改变到有效紧张。在深水里，内部压力在管理起床人使用了一个主导的角色有效紧张并且推进静态的配置，当流入速度的效果是可以忽略的时。关于起床人海床相互作用，海床支持和磨擦效果被考虑，与到一个非线性的二次的弹簧建模的前者，允许正切僵硬矩阵的一致推导。，非线性的二次的春天作为起始的静电干扰用链状的答案的介绍申请例子表演侧面，在这个有限元素计划为quasi-Winkler-type橡皮海床基础建模的一个有效方法。

简介：Anumericalmodel,EvolutionEquationofMild-SlopeEquation(EEMSE)developedbyHsuetal.(2003),wasappliedtostudytheBraggreflectionofwaterwavesoveraseriesofrectangularseabed.ThreekeyparametersoftheBraggreflectionincludingthepeakcoefficientofprimaryBraggreflection,itscorrespondingrelativewavelength,andthebandwidth,haveshowntobeeffectiveindescribingthecharacteristicsoftheprimaryBraggreflection.ThecharacteristicsoftheBraggreflectionwereinvestigatedunderthevariousconditionscomprisingnumber,height,andspacingintervalofaseriesofrectangularseabed.TheresultsrevealthatthepeakofBraggreflectionincreaseswiththeincreaseofrectangularseabedheightandnumber,thebandwidthandtheshiftvalueoftheBraggreflectiondependontheincreaseoftherectangularseabedheightaswellasthedecreaseofrectangularseabednumber,andtherelativerectangularseabedspacingintherangof3and4couldproducehigherBraggreflection.Finally,acorrelativeandregressiveanalysisisperformedbyuseofthecalculateddata.Basedontheresultsoftheanalysis,empiricalequationswereestablished.Ourstudyresultscanprovideanappropriatechoiceofaseriesofrectangularseabedfieldforapracticaldesign.

简介：-Thecyclicrotationofprincipalstressdirectionwithaconstantamplitudeisthecharacteristicsofcyclicstressinseabeddepositinducedbytravellingwaves.Presentedinthepaperaretheresultsobtainedfromtestssimulatingthecyclicstresscharacteristics,withemphasislaidonthebuildupofporewaterpressureinsoilsamples.Regressionanalysisoftestdatashowsthattheporewaterpressurecanbeexpressedasthefunctionofthenumberofcyclesofcyclicloading,orasthefunctionofgeneralizedshearstrain.Usingtheresultsthusobtained,thepossibilityoffailureofseabeddepositundercyclicloadinginducedbytravellingwavescanbeevaluated.Thecomparisonwiththeresultsofconventionalcyclictorsionalsheartestsshowsthatneglectoftheeffectofthecyclicrotationoftheprincipalstressdirectionwillresultinconsiderableover-estimationofthestabilityofseabeddeposit.

简介：

简介：在经历8天的联合潮汐的电流，循环和波浪行动以后，搜索包围自由地在1月在华东海(ECS)在沙的海床上休息的柱体目标的深度数字地用设计为的DRAMBUIE模型被预言广泛地搜索埋葬，它是使用并且验证由在原处实验。在数字集成的时期期间，timet的值通常是可变的在每次，经由特殊走时间的途径的步由这份报纸发展了消除时间错误。潮汐的当前的速度，波浪在ECS的轨道的速度和平均深度的发行量被数字模拟与沿海的河口和海洋模型(ECOM)获得了，模仿的波浪Nearshore(天鹅)模型和地区性的海洋建模系统(ROMS)分别地当模特儿。有影响的因素在的控制实验和几个理想化的测试用例搜索深度表明主导的水动力学因素是在在正常天气条件下面的ECS的潮汐的电流，并且本地人上的循环和波浪运动搜索的架的影响能几乎与自台湾东面的菲律宾海流向日本的暖流的高速度的主流流动的自台湾东面的菲律宾海流向日本的暖流区域的一个例外被忽略。这也被显示在沙的沉积，分发将近搜索深度跟随潮汐的水流的模式，当时第二等的影响因素在上搜索深度看起来是在ECS的沙的沉积的谷物尺寸。沉积谷物尺寸上的数字测试进一步证明那么更好的沙容易搜索的更多，和一个增加的趋势为与谷物尺寸的减小搜索深度由于更大的大小的粒子的强加的电阻被显示。三个方面由这篇论文探索了，包括在防卫研究机构矿埋葬环境(DRAMBUIE)模型，的实验方程输入和填入过程的精确性能严重地影响预言搜索包围自由地在ECS在沙的海床上休息的柱体目标的深度。

简介：Ascientifichypothesisisproposedandpreliminarilyverifiedinthispaper:underthedrivingofseepageflows,theremightbeaverticalmigrationoffine-grainedsoilparticlesfrominteriortosurfaceofseabed,whichisdefinedas‘sub-bottomsedimentpumpaction’inthispaper.FieldexperimentswereperformedtwiceontheintertidalflatoftheYellowRiverdeltatostudythisprocessviabothtrappingthepumpedmaterialsandrecordingtheporepressuresinthesubstrate.Experimentalresultsarequiteinterestingaswedidobserveyellowslurrywhichismainlycomposedoffine-grainedsoilparticlesappearingontheseabedsurface;seepagegradientswerealsodetectedintheintertidalflat,undertheactionoftidesandsmallwindwaves.Preliminaryconclusionsarethat‘sedimentpump’occurswhenseepageforceexceedsacertainthreshold:firstly,itisbigenoughtodisconnectthesoilparticlesfromthesoilskeleton;secondly,thedegreeofseabedfluidizationorbioturbationisbigenoughtoprovidepreferredpathsforthedetachedmaterialstomigrateupwards.Thentheywouldbefirstlypumpedfrominteriortothesurfaceofseabedandtheneasilyre-suspendedintooverlyingwatercolumn.Influentialfactorsof‘sedimentpump’aredeterminedashydrodynamics(waveenergy),degreeofconsolidation,indexofbioturbation(permeability)andcontentoffine-grainedmaterials(sedimentaryage).Thisnewperspectiveof‘sedimentpump’mayprovidesomeimplicationsforthemechanisminterpretationofseveraluncleargeologicalphenomenaintheYellowRiverdeltaarea.