不同截面形状柱体流致振动的CFD数值模拟

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1、第26卷第4期Vol.26No.4工程力学2009年4月Apr.2009ENGINEERINGMECHANICS7文章编号：1000-4750(2009)04-0007-09不同截面形状柱体流致振动的CFD数值模拟1*1,23徐枫，欧进萍，肖仪清(1.哈尔滨工业大学土木工程学院，黑龙江，哈尔滨150090；2.大连理工大学土木水利学院，辽宁，大连116024；3.哈尔滨工业大学深圳研究生院，广东，深圳518055)摘要：利用计算流体动力学(CFD)方法数值模拟Re200时不同截面形状弹性支撑柱体的流致振动现象。柱体运动简化为质量-弹簧

2、-阻尼系统。柱体周围流场采用Fluent求解，将Newmark-方法代码写入用户自定义函数(UDF)求解振动方程，柱体与流场间的非线性耦合作用通过动网格技术来实现。研究不同截面形状对柱体振动形式的影响，圆柱和六边形柱在整个频率比变化范围内始终表现为涡激振动，而方柱和三角形柱随频率比的增大则发生由驰振向涡激振动的转化，捕捉到转化的临界频率比。考虑了流向振动对横向振动的影响，得到了两自由度模型柱体的质心运动轨迹，结果表明柱体以横向振动为主。分析了气动力系数、位移特征值和尾流区涡结构随频率比的变化，获得“拍”和“相位开关”等重要现象，验证了

3、该文数值模拟方法的正确性。关键词：驰振；涡激振动；动网格；两自由度模型；UDF中图分类号：O351.2文献标识码：ACFDNUMERICALSIMULATIONOFFLOW-INDUCEDVIBRATIONWITHDIFFERENTCROSS-SECTIONCYLINDER1*1,23XUFeng,OUJin-ping,XIAOYi-qing(1.SchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,Heilongjiang150090,China;2.SchoolofC

4、ivil&HydraulicEngineering,DalianUniversityofTechnology,Dalian,Liaoning116024,China;3.HarbinInstituteofTechnologyShenzhenGraduateSchool,Shenzhen,Guangdong518055,China)Abstract:Flow-inducedvibrationsofcylinderswithdifferentcross-sectionswereinvestigatedbyemployingaCFDnumer

5、icalsimulationatRe200.Thecylinders’motionwasmodeledbyamass-spring-dampersystem.TheflowfieldwascalculatedusingFluentsoftwareandthevibrationequationofthecylinderwassolvedbytheNewmark-method,whichwasmanuallywrittenintoaUser-Defined-Function(UDF).Thenonlinearcouplingintera

6、ctionsbetweenthecylinderandtheflowfieldwerestudiedthroughadynamicmeshmodel.Theinfluenceofthedifferentcrosssectionalshapestotheformsofvibrationwasinvestigated.Thecircularandhexagonalcylindersexhibitvortex-inducedvibrationsinthewholerangeofthefrequencyratio.Forthesquareand

7、trianglecylinders,thevibrationalformchangesfrom‘galloping’tovortexinducedvibrationasthefrequencyrationincreases,andthecriticalfrequencyratioiscaptured.Whentheinfluenceofstreamwisevibrationontransversevibrationwastakenintoconsideration,thelocusofthecylinder’scentroidisobt

8、ainedandtheresultsshowthattransversevibrationofthecylindertakespredominance.Thepresentpaperdiscussesthe