低质量比下二维细长椭圆柱的流致振动数值模拟研究

海豹可以在视听条件受限的环境中依靠晶须来识别和追踪水中游鱼，对其进行研究将有助于开发研制新型水下探测器。由于晶须是具有7个表面特征参数的复杂结构，因此在研究和设计时与晶须截面等效的椭圆柱是值得考虑的替代方案。故本文以揭示椭圆柱水力探测机理为目的，研究柱体与晶须类似的涡激振动干扰信号抑制机理和超灵敏尾激振动响应机制。采用有限体积法，对具有晶须等效直径的细长椭圆柱在均匀流场中的涡激振动问题和在尾迹流场中的尾激振动问题进行数值仿真计算，准确模拟柱体随来流的流固耦合运动，探讨仿生晶须传感器对来流信号的响应规律。主要研究工作如下：

（1）对均匀来流作用下的细长椭圆柱的涡激振动问题进行数值模拟。主要研究约化速度和质量比对椭圆柱结构动力响应的影响以及柱体响应中的滞回现象，对柱体的振动响应规律、升阻力系数、频率响应、运动轨迹以及流场分布进行了分析。研究结果表明，细长椭圆柱的涡激振动仅存在下分支响应，最大响应振幅显著小于圆柱；质量比不是影响椭圆柱振动响应的主要因素；椭圆柱的尾涡脱落一直维持2S模态，仅在锁定开始时为C(2S)模态，对应一个极窄的滞回跳跃区。

（2）对均匀来流作用下的细长椭圆柱阵列的涡激振动问题进行数值模拟。主要研究约化速度对多椭圆柱结构动力响应的影响，对各个柱体的振动响应规律、升阻力系数、频率响应、运动轨迹以及流场分布进行了分析。研究结果表明，阵列中的上游椭圆柱的响应形态与单个椭圆柱工况接近，仍具有良好的减阻抑振能力；而下游椭圆柱的响应形态则受上游柱体尾涡和两侧流场的影响，在两方向的受力和振幅趋势均出现较大区别，并且在流向方向产生了极高振幅。

（3）对上游静止圆柱-下游自由振动椭圆柱的尾激振动问题进行数值模拟。主要研究尺寸比、间距比和约化速度对下游椭圆柱结构动力响应的影响，对柱体的振动响应规律、升阻力系数、频率响应、运动轨迹以及流场分布进行了分析。研究结果表明，椭圆柱的振动响应频率始终等于上游圆柱的尾涡频率；尺寸比和间距比的增大均改变了尾激振动系统的流动状态，重附着模式通过影响柱体周围的压力分布，使其产生了更强的两方向受力和振动响应，共同脱落模式的流向振动响应相较而言被显著抑制，而延展体脱落模式的两方向受力和振动响应均被抑制。

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