Abstract The present work investigates the underlying flow physics behind dynamical transitions that take place in the flow-field around a plunging foil as the nondimensional plunge velocity ( κ h ) is increased. The unsteady flow-field is seen to undergo a transition from periodicity to chaos through a quasi-periodic route. Numerical simulations have been performed at different parametric regimes associated with the different dynamical states, using an in-house flow solver developed based on discrete forcing type Immersed Boundary Method (IBM). Results obtained using the IBM methodology are compared both qualitatively and quantitatively with those from a well-validated body-fitted Arbitrary Lagrangian-Eulerian (ALE) approach. This study explores the scope of body non-conformal mesh methods in comparison to body fitted approaches in capturing complex flow topologies, especially, during aperiodic flow regimes. In the discrete direct forcing type IBM solver developed in the present study, application of the momentum forcing and mass/source sink terms at all the grid points inside the solid domain is seen to capture various unsteady flow-mechanisms accurately. These mechanisms are crucial in dictating the dynamics and they play key roles in triggering the aperiodic onsets and sustaining them.

中文翻译：

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使用浸入边界法捕获扑翼流场中的动态转变

摘要 目前的工作研究了随着无量纲插入速度 (κ h ) 的增加，在插入箔周围的流场中发生的动力学转变背后的基本流动物理学。非定常流场通过准周期路径经历了从周期性到混沌的转变。使用基于离散强迫型浸入边界法 (IBM) 开发的内部流动求解器，在与不同动态状态相关的不同参数状态下进行了数值模拟。使用 IBM 方法获得的结果与来自经过充分验证的贴身任意拉格朗日-欧拉 (ALE) 方法的结果进行定性和定量比较。本研究探讨了与体拟合方法相比，体非共形网格方法在捕获复杂流拓扑方面的范围，尤其是在非周期性流态期间。在本研究开发的离散直接强迫型 IBM 求解器中，在固体域内的所有网格点上应用动量强迫和质量/源汇项可以准确地捕捉各种非定常流动机制。这些机制对于决定动力学至关重要，它们在触发和维持非周期性发作方面发挥着关键作用。在固体域内的所有网格点上应用动量强迫和质量/源汇项可以准确地捕捉各种非定常流动机制。这些机制对于决定动力学至关重要，它们在触发和维持非周期性发作方面发挥着关键作用。在固体域内的所有网格点上应用动量强迫和质量/源汇项可以准确地捕捉各种非定常流动机制。这些机制对于决定动力学至关重要，它们在触发和维持非周期性发作方面发挥着关键作用。