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采用RANS方法,结合SST k-ω湍流模型,对不同顺流向与横顺流向固有频率的比值(即固有频率比,fnx/fny)条件下低质量比圆柱体的双自由度涡激振动进行了二维数值模拟。圆柱体的质量比为2.6,雷诺数范围为2 500~18 750,相应的约化速度范围为2~15,包括了经典试验中出现的整个锁定范围。通过研究发现,固有频率比是影响振动特性的重要参数,随着固有频率比的增加,响应幅值逐渐降低且向更高的约化速度偏移;在低约化速度范围内,固有频率比对顺流向和横流向振动之间的相位差以及升力频率有较大影响,从而得到各种不同偏向的8字形轨迹;最后对不同固有频率比条件下的尾涡模式进行了讨论,给出了对应不同约化速度时的尾涡模式。 相似文献
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In this study,a new analytical approach is developed to analyze the free nonlinear vibration of conservative two-degree-of-freedom(TDOF) systems.The mathematical models of these systems are governed by second–order nonlinear partial differential equations.Nonlinear differential equations were transferred into a single equation by using some intermediate variables.The single nonlinear differential equations are solved by using the first order of the Hamiltonian approach(HA).Different parameters,which have a significant impact on the response of the systems,are considered and discussed.Some comparisons are presented to verify the results between the Hamiltonian approach and the exact solution.The maximum relative error is less than 2.2124 % for large amplitudes of vibration.It has been established that the first iteration of the Hamiltonian approach achieves very accurate results,does not require any small perturbations,and can be used for a wide range of nonlinear problems. 相似文献
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