This paper deals with the analysis of the grid generated turbulence on flow induced vibration response of the parallel triangular tube bundle with pitch ratio of 1.54. Turbulence characteristics of the upstream flow can highly influence the stability behavior of a single flexible as well as multiple flexible tubes in early rows of tube bundle. Experimentation have been performed in the wind tunnel with the free stream velocity ranging from 0 to 8.9 m/s. Distinct amplitude behavior for the monitored tube has been observed for each row in both streamwise and the transverse direction. With the increase in the upstream turbulence, the stability threshold of the monitored tube tends to be delayed for single flexible case, however for the multiple flexible case the stability threshold tends to move towards early values. This indicates the importance of stiffness mechanism in generating instability in the monitored tube, which is enhanced by upstream turbulence. Surprisingly, upstream turbulence is strongly affecting frequency response of the tube bundle. Spectral analysis depicts that translational mode dominates rocking mode for single flexible tube bundle for all cases even for highest turbulence intensities. However, for multiple flexible tube case the rocking mode tends to dominant for the fourth row subjected to highest turbulence intensity of 16.5%. This may be due to the uneven distribution of forces on the tube length due to upstream turbulence and turbulence generated by first three rows which intern to excites the rocking mode. It is revealed that multiple flexible tube bundle dominates rocking mode frequency amplitude because of fluid forces generated by tube to tube coupling. The rocking mode become significant which reflects the importance of stiffness mechanism for generating instability in the monitored tube. Stability diagram delineates that for higher upstream turbulence intensities, the data points lies on the upper side of stability boundary in unstable region for multiple flexible tube case and under the stability boundary for single flexible tube case. The results depicted that the previous theoretical stability models either underestimate or overestimates the stability behavior of tube bundle and hence requires modification in the model to predict the stability boundaries for higher upstream turbulence intensities.

本文针对节距比为1.54的平行三角管束的流动引起的振动响应，分析了网格产生的湍流。上游流动的湍流特性会极大地影响管束早期排中的单个挠性管以及多个挠性管的稳定性。在风洞中进行了自由流速度为0到8.9 m / s的实验。对于每行在水流方向和横向方向上都观察到了受监控管的不同幅度行为。随着上游湍流的增加，被监测管的稳定性阈值倾向于在单个柔性情况下被延迟，但是对于多个柔性情况，稳定性阈值倾向于朝着早期值移动。这表明刚度机制在受监控管中产生不稳定性方面的重要性，而上游湍流则加剧了这种不稳定性。出乎意料的是，上游湍流强烈影响管束的频率响应。频谱分析表明，对于所有情况，即使对于最高湍流强度，平移模式也对单个挠性管束的摇摆模式起主导作用。然而，对于多挠性管的情况，在最高湍流强度为16.5％的情况下，摇摆模式倾向于在第四排占主导地位。这可能是由于上游湍流和由前三行产生的湍流引起的在管长度上的力的不均匀分布，前三行引起了摇摆模式。揭示了由于管对管耦合产生的流体力，多个挠性管束在摇摆模式频率振幅中占主导地位。摇摆模式变得很重要，这反映了刚度机制对于在被监测管中产生不稳定性的重要性。稳定性图描述了对于更高的上游湍流强度，数据点位于不稳定区域的稳定边界的上侧（对于多挠性管壳而言），而在稳定边界下则对于单挠性管壳而言。结果表明，先前的理论稳定性模型低估或高估了管束的稳定性，因此需要对模型进行修改以预测较高上游湍流强度的稳定性边界。摇摆模式变得很重要，这反映了刚度机制对于在被监测管中产生不稳定性的重要性。稳定性图描述了对于更高的上游湍流强度，数据点位于不稳定区域的稳定边界的上侧（对于多挠性管壳而言），而在稳定边界下则对于单挠性管壳而言。结果表明，先前的理论稳定性模型低估或高估了管束的稳定性，因此需要对模型进行修改以预测较高上游湍流强度的稳定性边界。摇摆模式变得很重要，这反映了刚度机制对于在被监测管中产生不稳定性的重要性。稳定性图描述了对于更高的上游湍流强度，数据点位于不稳定区域的稳定边界的上侧（对于多挠性管壳而言），而在稳定边界下则对于单挠性管壳而言。结果表明，先前的理论稳定性模型低估或高估了管束的稳定性，因此需要对模型进行修改以预测较高上游湍流强度的稳定性边界。数据点位于多管柔性管壳不稳定区域的稳定边界的上侧，而单管柔性管壳稳定边界的下侧。结果表明，先前的理论稳定性模型低估或高估了管束的稳定性，因此需要对模型进行修改以预测较高上游湍流强度的稳定性边界。数据点位于多管柔性管壳不稳定区域的稳定边界的上侧，而单管柔性管壳稳定边界的下侧。结果表明，先前的理论稳定性模型低估或高估了管束的稳定性，因此需要对模型进行修改以预测较高上游湍流强度的稳定性边界。