Abstract Vibrations of tube bundles in heat exchange equipment, such as nuclear steam generators and tube-and-shell type heat exchangers, are often caused by unsteady fluid forces. The study of flow-induced vibration excitation forces on tubes is necessary for understanding the fluid-elastic instability phenomenon. In this paper, a forced vibration method is introduced to investigate unsteady motion-dependent fluid forces in a normal triangular tube array with the pitch ratio of 1.32 that is subjected to water crossflow. Fluid force behaviors of a single flexible central tube and its lift response spectra are investigated in various forced vibration modes. In a seven-tube kernel unit, coupling effects of surrounding tubes on the central tube are also discussed. Results show that the lift force on a flexible vibrating tube mainly depends on the vibration amplitude of tube itself in the lift direction, and is less affected by the degree of freedom, the rotation direction and the main vibration direction of tube vibration. The frequency spectrum of lift responses is dominated by two main frequencies: the vortex alternating frequency and the tube natural frequency. Surrounding flexible tubes increase higher order harmonics of the periodic lift force fluctuations of the central tube. Compared with rear-column tubes, vibrations of the front-column tubes have more significant effects on lift force responses of the tube kernel, which facts causes strong coupling to promote the fluid-elastic instability of tubes.

中文翻译：

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受迫振动中法向三角管阵列中流体力波动的时域和频域分析

摘要 核蒸汽发生器、管壳式换热器等换热设备中管束的振动往往是由非定常流体力引起的。研究流体引起的管子振动激发力对于理解流体弹性不稳定现象是必要的。在本文中，引入受迫振动方法来研究受水错流影响的节距比为 1.32 的法向三角管阵列中的非定常运动相关流体力。在各种受迫振动模式下研究了单个柔性中心管的流体力行为及其升力响应谱。在一个七管核单元中，还讨论了周围管对中心管的耦合效应。结果表明，柔性振动管上的升力主要取决于管本身在升力方向的振动幅值，受自由度、旋转方向和管振动主振动方向的影响较小。升力响应的频谱由两个主要频率决定：涡旋交变频率和管子固有频率。周围的柔性管增加了中心管周期性升力波动的高次谐波。与后柱管相比，前柱管的振动对管核升力响应的影响更显着，这会导致强耦合，促进管的流体弹性失稳。管振动的旋转方向和主振动方向。升力响应的频谱由两个主要频率决定：涡旋交变频率和管子固有频率。周围的柔性管增加了中心管周期性升力波动的高次谐波。与后柱管相比，前柱管的振动对管核升力响应的影响更显着，这会导致强耦合，促进管的流体弹性失稳。管振动的旋转方向和主振动方向。升力响应的频谱由两个主要频率决定：涡旋交变频率和管子固有频率。周围的柔性管增加了中心管周期性升力波动的高次谐波。与后柱管相比，前柱管的振动对管核升力响应的影响更显着，这会导致强耦合，促进管的流体弹性失稳。周围的柔性管增加了中心管周期性升力波动的高次谐波。与后柱管相比，前柱管的振动对管核升力响应的影响更显着，这会导致强耦合，促进管的流体弹性失稳。周围的柔性管增加了中心管周期性升力波动的高次谐波。与后柱管相比，前柱管的振动对管核升力响应的影响更为显着，这会产生强耦合，促进管的流体弹性失稳。