水动力计算软件-AQWA-培训

©2006ANSYS,Inc.Allrightsreserved.1ANSYS,Inc.Proprietary25th–29thseptember2006©2006ANSYS,Inc.Allrightsreserved.2ANSYS,Inc.Proprietary目录培训内容:•AQWA程序分析能力•理论背景•模拟技术modellingtechniques•分析过程•分析数据的准备•结果的输出内容和解释•实例©2006ANSYS,Inc.Allrightsreserved.3ANSYS,Inc.Proprietary客户RegulatoryBodies•ABS(US),LloydsRegister(UK)Operators•BP,USNavy,NavionEngineeringCompanies•JohnBrownHydrocarbons,KellogBrownandRoot•ArupEnergy,FriedeandGoldman•MitsubishiHeavyIndustries,KawasakiHeavyIndustries•PIRauma,Intec•WorleyEngineering,IHCGusto,SBM©2006ANSYS,Inc.Allrightsreserved.4ANSYS,Inc.Proprietary客户Consultants:•ArmstrongTechnology•JPKenny•JJMcMullen•Moffatt&Nichol•NobleDenton•HanPadron•Atkins•AMOG•D2M•Atlantia•MossMaritime•Inocean©2006ANSYS,Inc.Allrightsreserved.5ANSYS,Inc.ProprietaryAQWA程序介绍•AQWA的程序结构和分析能力–AQWALINE-•3-Ddiffraction&radiationanalysisprogramforwaveforceandstructureresponsecalculations;hydrostaticanalysis–AQWALIBRIUM-•Structureequilibriumpositionandforcebalancecalculations;eigenmodeanddynamicstabilityanalysis–AQWAFER-•Spectralanalysisofstructuremotion(wavefrequencyor/anddriftfrequency)andmooringtensioninirregularwaves©2006ANSYS,Inc.Allrightsreserved.6ANSYS,Inc.ProprietaryAQWA程序介绍–AQWANAUT-•Timedomainprogramforwavefrequencystructuremotionandmooringtensionanalysesinregularwaves–AQWADRIFT-•Timedomainprogramfordriftfrequencyandwavefrequencystructuremotionandmooringtensionanalysisinirregularwaves–AQWAGraphicalSupervisor(AGS)-•AQWApreandpostprocessor;on-lineanalysis–AQWAWAVE-•InterfacebetweenhydrodynamicprogramandFEprogramtotransferwaveloadsfromAQWALINEtoaFEmodelforstructuralstrengthanalysis©2006ANSYS,Inc.Allrightsreserved.7ANSYS,Inc.ProprietaryAQWA程序介绍LINELIBRIUMFERNAUTDRIFTWAVEASAS(FEmodel)GeneralRelationsbetweenPrograms©2006ANSYS,Inc.Allrightsreserved.8ANSYS,Inc.ProprietaryTypicalAQWAModel(1)-MooredTanker©2006ANSYS,Inc.Allrightsreserved.9ANSYS,Inc.ProprietaryTypicalAQWAModel(2)-SemiSub©2006ANSYS,Inc.Allrightsreserved.10ANSYS,Inc.ProprietaryAQWAResult(1)-Force&ResponseCurves©2006ANSYS,Inc.Allrightsreserved.11ANSYS,Inc.ProprietaryAQWAResult(2)-PressureContour©2006ANSYS,Inc.Allrightsreserved.12ANSYS,Inc.ProprietaryAQWAResult(3)-ShearForce&BendingMoment©2006ANSYS,Inc.Allrightsreserved.13ANSYS,Inc.ProprietaryAQWALINE介绍–AQWA-LINE是3D衍射和辐射分析程序–通过大量的板格来描述结构–在每个板格中心有源点（asource），程序会求解受到如下边界条件时源点的强度:•没有水流穿过船体•没有水流穿过海底•板格为自由面–这样就可以在任意点计算出压力和速度©2006ANSYS,Inc.Allrightsreserved.14ANSYS,Inc.ProprietaryAQWALINE理论–AQWALINE的3D线性波理论•假设–流体无旋，不可压–小波（smallwaveelevation）•速度势能控制方程•体的边界条件)(02V0).(nVs©2006ANSYS,Inc.Allrightsreserved.15ANSYS,Inc.ProprietaryAQWALINE理论•自由表面运动条件线性化之后•自由表面动力条件0)(.)(..0)(ztzeiDtzD0ztconstgpt.21©2006ANSYS,Inc.Allrightsreserved.16ANSYS,Inc.ProprietaryAQWALINE理论线性化之后组合自由表面条件•海底边界条件0gt02gzwatershallowforbedseadzatzwaterdeepforzwhen)(00©2006ANSYS,Inc.Allrightsreserved.17ANSYS,Inc.ProprietaryAQWALINE理论•辐射条件辐射条件是一种物理状态，使波不会在错误的方向上传递，如水穿透船体，从而避免数上的不确定性。•数值方法–势能项的线性叠加式中：下标I是入射波，d是衍射波,j=1,2,…,6是6个自由度的辐射波，x是单位波幅下结构的运动.tijjjdItiexe].)[(61©2006ANSYS,Inc.Allrightsreserved.18ANSYS,Inc.ProprietaryAQWALINE理论–对于有限水深d，入射波的势能为式中k是波数，定义为:–使用脉冲源分布（pulsatingsourcedistribution）求解衍射和辐射波势能)cosh()](cosh[)sincos(kdeedzkigetiyxiktiI)tanh(2kdgkdszyxGzyxs),,;,,(41),,(©2006ANSYS,Inc.Allrightsreserved.19ANSYS,Inc.ProprietaryAQWALINE理论式中：б是辐射体强度（sourcestrength）;S是入水结构面;(x,y,z)为流域中域点的坐标;(ζ,η,ς)是S上源点坐标;G为格林函数，是求解Laplace方程的基础，并且满足所有边界条件（除了体边界条件）.G可以表达为:)()(cosh)(cosh)((2)()(cosh)(cosh)cosh()sinh()(211),,;,,(022)2200'krJdkdzkdkkidrJdzdddepvRRzyxGd©2006ANSYS,Inc.Allrightsreserved.20ANSYS,Inc.ProprietaryAQWALINE理论式中pv表示积分的principalvalue;J0是Bessel函数的第一项)tanh(/2kdkg222'22222)2()()()()()()()(dzyxRzyxRyxr©2006ANSYS,Inc.Allrightsreserved.21ANSYS,Inc.ProprietaryAQWALINE理论在每个板格结构表面上的源强度（sourcestrength）假设为常数，通过体边界条件求解积分方程计算:对于衍射势能，在结构表面由于入射势能产生的法向速度会变为零，而所减少的法向速度会转化为结构运动.dsnzyxGzyxnzyxs),,;,,(41),,(21),,(©2006ANSYS,Inc.Allrightsreserved.22ANSYS,Inc.ProprietaryAQWALINE理论•压力和第一阶波浪力的计算一旦计算了源点强度和势能，从线性化的Bernoulli方程中可以计算每个板格的水动力压力:第一阶波浪力是通过在体表面上进行积分得到的tp©2006ANSYS,Inc.Allrightsreserved.23ANSYS,Inc.Proprietary•二阶平均漂浮力计算–远场求解（Farfieldsolution）(动量守恒方法，只用于水平力）):式中SR是在流场结构周围的垂直圆柱边界其半径为R，是SR的流体体积，Themeanforceisthetimeaverageoftheaboveexpressionandthefirstordertermbecomeszero.Thepressureincludesthenon-lineartermintheBernoulliequationandthereforewillnotdisappear.SdpdSVVdtVSdpVddtdFRSnRSnRSnstrc)2(dtVAQWALINE理论©2006ANSYS,Inc.Allrightsreserved.24ANSYS,Inc.ProprietaryAQWALINE理论–近场求解(压力对于六个自由度进行积分方法):式中WL为水线位置;ζr是相关波表面（relativewavesurfaceelevation）;S0水下结构表面;X结构表面的运动;MS结构的质量;R是结构的旋转矩阵;是结构中心加速度...0202)2(..).(5.05.0gsSSWLrstrcXRMdSntXdSndlngF..gX©2006ANSYS,Inc.Allrightsreserved.25ANSYS,Inc.ProprietaryAQWALINE理论QuadraticTransferFunction(QTF)–ComponentsatbothdifferenceandsumfrequenciesEachwithrealandimaginaryparts