简介:Thispaperpresentsanimprovedunstructuredgridimmersedboundarymethod.Theadvantagesofbothimmersedboundarymethodandbodyfittedgridswhicharegeneratedbyunstructuredgridtechnologyareusedtoenhancethecomputationefficiencyoffluidstructureinteractionincomplexdomain.TheNavier-StokesequationwasdiscretizedspaciallywithcollocatedfinitevolumemethodandEulerimplicitmethodintimedomain.TherigidbodymotionwassimulatedbyimmersedboundarymethodinwhichthefluidandrigidbodyinterfaceinteractionwasdealtwithVOS(volumeofsolid)method.AnewVOScalculationmethodbasedongraphwaspresentedinwhichbothimmersedboundarypointsandcrosspointswerecollectedinarbitraryordertoformagraph.Themethodisverifiedwithflowpastoscillatingcylinder.
简介:Inthenormaloperationcondition,aconventionalsquare-rootcubatureKalmanfilter(SRCKF)givessufficientlygoodestimationresults.However,ifthemeasurementsarenotreliable,theSRCKFmaygiveinaccurateresultsanddivergesbytime.ThisstudyintroducesanadaptiveSRCKFalgorithmwiththefiltergaincorrectionforthecaseofmeasurementmalfunctions.Byproposingaswitchingcriterion,anoptimalfilterisselectedfromtheadaptiveandconventionalSRCKFaccordingtothemeasurementquality.Asubsystemsoftfaultdetectionalgorithmisbuiltwiththefilterresidual.Utilizingaclearsubsystemfaultcoefficient,thefaultysubsystemisisolatedasaresultofthesystemreconstruction.Inordertoimprovetheperformanceofthemulti-sensorsystem,ahybridfusionalgorithmispresentedbasedontheadaptiveSRCKF.Thestateanderrorcovariancematrixarealsopredictedbythepriorifusionestimates,andareupdatedbythepredictedandestimatedinformationofsubsystems.Theproposedalgorithmswereappliedtothevesseldynamicpositioningsystemsimulation.TheywerecomparedwithnormalSRCKFandlocalestimationweightedfusionalgorithm.ThesimulationresultsshowthatthepresentedadaptiveSRCKFimprovestherobustnessofsubsystemfiltering,andthehybridfusionalgorithmhasthebetterperformance.Thesimulationverifiestheeffectivenessoftheproposedalgorithms.
简介:文章从《STCW95公约》对船员在语言方面的新要求出发,联系目前航海院校英语教学实际,提出了航海院校英语教学改革的对策。