The untethered swimming performance of a two-dimensional squid-inspired swimmer is studied. Our model includes fully-coupled fluid-structure interaction and an idealized activation algorithm that drives periodic shape change of the body. We present results of both escape jetting via a single deflation-coasting motion and long-distance swimming via repeated inflation-deflation cycles. In both cases added-mass-related force is found to contribute significantly to thrust generation. Moreover, we find that the increase of the jet speed and oscillation frequency leads to higher swimming velocity. This, however, is achieved at the cost of reduced propulsion efficiency (i.e. higher cost of transport). During long-distance swimming, the system experiences three successive stages, acceleration, steady-state swimming, and off-track swimming caused by symmetry-breaking instability in the wake. Associated with these stages, three wake patterns are observed, nozzle-vortex-dominated wake, transit wake, and asymmetrical wake.

中文翻译：

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鱿鱼启发的游泳者在自由泳中的动力学。

研究了以鱿鱼为灵感的二维游泳者的无束缚游泳性能。我们的模型包括全耦合的流体-结构相互作用和理想化的激活算法，该算法可驱动身体的周期性形状变化。我们介绍了通过单个放气-降落运动逃逸喷射和通过重复的充气-放气循环进行长距离游泳的结果。在这两种情况下，都发现与质量有关的力对推力的产生有很大贡献。此外，我们发现喷射速度和振荡频率的增加导致更高的游泳速度。然而，这是以降低的推进效率为代价（即更高的运输成本）来实现的。在长距离游泳期间，系统会经历三个连续的阶段：加速，稳态游泳，以及尾流中对称破坏不稳定性引起的偏离轨道游泳。与这些阶段相关联，观察到三种尾流模式：喷嘴涡流为主的尾流，过渡尾流和不对称尾流。