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ANSYSTOAQWAMODELTRANSLATORANSYS模型文件转换AQWA-LINE标准输入文件1.INTRODUCTION引言ItispossibletouseclassicANSYStocreateanAQWAradiation/diffractionmodel.AnyofthetoolsavailableinWorkbenchorANSYScanbeusedtocreatethemodel.OncethemodeliscreatedanAQWAinputfilecanbewrittenoutusingamacrosuppliedwithANSYS.使用传统的ANSYS产生AQWA辐射/绕射模型是可行的。在Workbench或ANSYS中有工具能够建模。一旦模型建立了，使用ANSYS的宏命令'ANSTOAQWA'可以自动产生AQWA-LINE的输入文件（将.aqwa修改为.dat格式即可）。2.MODELDESCRIPTION模型描述ThemodelmustbemeshedwiththemeshthatyouwishtousefortheAQWAanalysis.Ifyouareworkingfromamodelcreatedforastructuralanalysis,itwillprobablybenecessarytore-meshthemodelasthestructuralmeshislikelytobefinerthanisneedforadiffractionanalysis.必须使用与AQWA中分析单元类型相同的单元来划分模型的网格。如果你的模型建于ANSYS结构分析，可能会需要不断重新划分网格直到网格尺寸、数目等满足绕射分析的要求。Thereshouldbealineofnodesatthewaterline,althoughthesenodesdonotneedtocoincidewithnodesonthestructuralmodel.Thetranslationmacrowillonlymakediffractingthoseelementsthatareentirelybelowthewaterline.Iftherearenowaterlinenodestherewillbenodiffractingelementsatthewaterline,whichwillseverelyreducetheaccuracyofthediffractionanalysis.吃水线上应该有一行节点，尽管这些节点不需要符合结构模型的节点。转换宏会仅仅将位于吃水线以下的单元制作成绕射单元（DIFF）。如果没有吃水线节点，则吃水线上不会有绕射单元，这会严重的减少绕射分析的准确性。Allthepanelelementsbelowthewatermusthavetheirnormalspointingoutwards.水下所有的面元必须指示外表面。InAQWAtheverticalaxisisalwaystheZ-axis.ThetranslatorcanconvertamodelwitheitherYorZ-axesvertical,buttheX-axismustbehorizontalandpreferablyshouldbealongthefore/aftaxisofthevessel.在AQWA中垂向轴总是Z轴。转换器能转换一个以Y或Z为垂直方向的模型，但是X轴必须是水平方向的，最好是沿着船的头/尾轴。IfthestructureissymmetricandyouwishtousetheSYMXorSYMYcardsinAQWA,youmustonlyselect½or¼ofthemodelasappropriate.IfyoumodelacompletevesselandspecifyXsymmetry,theAQWAmodelwillcontaintwosetsofcoincidentelements.如果结构是对称的，你希望使用AQWA的SYMX或SYMY卡片,你必须仅仅选择1/2或1/4模型。如果你建立一个完整的船模，指定X方向对称，则AQWA模型将会包含2套一致的单元。3.ELEMENTMAPPING绘制单元ThetranslatormapsSHELL41,PLANE42,SHELL43,SHELL63,SHELL181elementstopanels,andPIPE16,PIPE20,PIPE59elementstoTUBEs.ItdoesnotrecognizeanyotherANSYSelementtypes.AnymaterialorgeometricpropertiescanbeusedfortheshellelementsasAQWAdoesnotneedanypropertiesatallandthetranslatordoesnotusethem.转换器能够绘制SHELL41,PLANE42,SHELL43,SHELL63,SHELL181面单元，及PIPE16,PIPE20,PIPE59管单元。它不识别其他任意的ANSYS单元类型。板壳单元使用的任意材料或几何性质，AQWA都不需要，转换器不会使用这些性质。TUBEelementsinAQWAhavematerialdensity,outsidediameter,wallthickness,addedmassanddragcoefficients,soappropriatepropertiesshouldbeusedintheANSYSmodel.PIPE59elementscanhaveaddedmassanddampingcoefficients,andthesewillbetransferred.NotethatANSYSusestheinertiacoefficientCM,whereasAQWAusestheaddedmasscoefficientCA,whereCM=(1+CA).Thiscorrectionismadeautomaticallybythetranslator.AQWA管单元具有材料密度，外径，壁厚，附加质量和阻力系数，所以ANSYS建模时应该定义正确的性质。PIPE59单元具有附加质量和阻力系数，这两项会被转换器写入*.DAT文件。注意：ANSYS使用惯性系数mC，但是AQWA使用附加质量系数aC，)1(amCC。转换器会自动修正数据。4.RUNNINGTHEMACRO运行宏命令Whenyouhavecreatedandmeshedamodelasdescribedabove,youcanrunthemacrotogenerateanAQWAinputfile.FirstselecttheelementsthatyouwanttoincludeintheAQWAmodel.Atthecommandlinetype“anstoaqwa”optionallyfollowedbyafilename.TheAQWAinputfilewillbecalled“file.aqwa”,wherefileisthenameofyourdatabaseorthefilenameyouhaveinput.Youwillthenbepromptedtoinputanumberofparametersinawindowasshownbelow.当你按照上面的描述建立模型并划分网格后，你能够运行转换宏来产生AQWA输入文件。首先选择你想要包含在AQWA模型中的单元。在命令行上输入‘ANSTOAQWA’命令，后面跟一个文件名。AQWA输入文件会是'文件名.aqwa'(实际就是.dat文件）。接着你会在弹出的如下窗口中输入一系列的参数。AQWA对网格的要求RulesforDistributionofDiffractionPlateElementsTheRULESforthedistributionofdiffractionpressureplateelementsoverthewettedbodysurfacefallintotwocategories.Thesemaybeclassifiedasrulesrelatingtotheoreticalconsiderationsandrulesrelatingtonumericalcomputationalconsiderations.Thehydrodynamicdiffraction/radiationfluidforcesarecalculatedbyusingadiscretedistributionoffluidSOURCESoverthewettedsurfaceofthebody(seeSection3.3).Thesesourcesarepositionedatthecentresoftheuserdefineddiffractionpressureplateelements.Thefollowingrulesrelategenerallytoplacementandsizingofplateelementswhichinturnreflectsonthedistributionofsources.绕射压力单元在湿表面的分布规则分为两类：考虑理论和数值计算的影响。水动力绕射/入射流体压力是使用整个湿表面上的源离散分布来计算的。这些源定位在用户所定义的绕射压力单元的中心位置。以下的规则主要与压力单元的放置和单元大小有关，反过来会影响源的分布。(A)RULESduetoTheoreticalConsiderations基于理论考虑的网格规则1Theplateelements,whichautomaticallygeneratesources,MUSTCOVERtheentiremeanwettedsurfaceofthebodyorbodies.Thebodymeanwettedsurfaceisthatpartofthebodywhichisincontactwiththefluidwhenthebodyisinanequilibriumorsteadystateposition.Thiswettedsurfacemustbebetweenthefluidfree-surfaceandthesea-bed.2Theplates,andhencesources,shouldbeCONCENTRATEDonthosepartsofthebodywhicharelikelytoexperiencehighfluidflow(e.g.thebowsectionoraftendsectionofaship).压力单元（或源）必须在浮体可能经受较高流体流动的部分分布密集（例如船尾或弓形部分）3PlatecharacteristicdimensionsshouldbeLESSTHAN1/7thOFTHEINCIDENTWAVELENGTH.Therefore,thelongestsideoftheplateelementshouldsatisfythiscriterion.面元的性能尺寸必须小于突发波高的七分之一，面单元的最长边应该满足这个准则4PlateelementsidedimensionsshouldbeLESSTHANthelocalradiusofcurvatureofthesurfacebodypartbeingmodelled.Thisconditioncannotbesatisfiedatsharpcornersandtheseareeffectivelyroundedoff(e.g.knucklesonaship’shull).面元边尺寸应该小于表面的局部曲率半径5Diffractingplatesmodellingthebodysu