The past decade witnessed a renewed interest in understanding the escape phenomenon in nonlinear oscillators. This is due to the emergence of new devices where escape of the dynamic trajectories from a potential well can be utilized as a trigger for switching and structural morphing. In this study, the basic characteristics of escape from a potential well for a circular cylinder undergoing vortex-induced vibrations is investigated via a computational model for low Reynolds number ranging between 70 and 250. The cylinder has a low mass ratio, zero structural damping, and is supported by a softening nonlinear spring. It is shown that the magnitude of the nonlinearity in the supporting spring has a substantial influence on the response behavior of the oscillator prior to escape, and that escape cannot occur for small values of the nonlinearity because the magnitude of the response in the lock-in region can never exceed the threshold amplitude necessary for escape. It is also shown that, when it happens, escape from the potential well typically occurs due to the transient trajectories overcoming the potential barrier. Thus, a steady-state analysis of the response behavior is not sufficient to accurately predict the flow speeds at which escape occurs. Finally, it is shown that escape occurs for a range of flow speeds which expands with the nonlinearity and shrinks with the mass ratio. Results presented in this study are fundamental to the design of flow-activated switches and morphing mechanisms.

过去十年见证了人们对理解非线性振荡器逃逸现象的新兴趣。这是由于新设备的出现，其中从势阱逃逸的动态轨迹可以用作切换和结构变形的触发器。在这项研究中，通过一个计算模型研究了在 70 到 250 之间的低雷诺数的圆柱体从势阱逃逸的基本特征。圆柱体具有低质量比，零结构阻尼，并由软化的非线性弹簧支撑。结果表明，支撑弹簧中非线性的大小对逸出前振荡器的响应行为有重大影响，并且对于较小的非线性值不会发生逃逸，因为锁定区域中的响应幅度永远不会超过逃逸所需的阈值幅度。还表明，当它发生时，通常会由于瞬态轨迹克服势垒而从势阱中逃逸。因此，响应行为的稳态分析不足以准确预测发生逃逸的流速。最后，它表明逃逸发生在一个流速范围内，该范围随非线性而扩大，随质量比而缩小。本研究中提出的结果是设计流激活开关和变形机制的基础。还表明，当它发生时，通常会由于瞬态轨迹克服势垒而从势阱中逃逸。因此，响应行为的稳态分析不足以准确预测发生逃逸的流速。最后，它表明逃逸发生在一个流速范围内，该范围随非线性而扩大，随质量比而缩小。本研究中提出的结果是流量激活开关和变形机制设计的基础。还表明，当它发生时，通常会由于瞬态轨迹克服势垒而从势阱中逃逸。因此，响应行为的稳态分析不足以准确预测发生逃逸的流速。最后，它表明逃逸发生在一个流速范围内，该范围随非线性而扩大，随质量比而缩小。本研究中提出的结果是流量激活开关和变形机制设计的基础。结果表明，逃逸发生在一定范围的流速下，该范围随非线性而扩大，随质量比而缩小。本研究中提出的结果是流量激活开关和变形机制设计的基础。结果表明，逃逸发生在一定范围的流速下，该范围随非线性而扩大，随质量比而缩小。本研究中提出的结果是流量激活开关和变形机制设计的基础。