Data from: From the track to the ocean: using flow control to improve marine bio-logging tags for cetaceans

Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal.生物记录标签（Bio-logging tags）是鲸目动物（cetaceans）研究的重要工具，但体表粘贴的标签不可避免会增加流体动力载荷。对于快速游泳的鲸类而言，标签可能产生可观的作用力，进而可能影响其行为与能量代谢，甚至导致标签提前脱落。过往研究曾采用流线型结构以降低流体动力载荷，但这类设计会加快标签上方的流体流速。这种非轴对称流动会产生较大的升力（lift forces，垂直于动物躯体方向），在高速游泳工况下，该升力会成为主导的作用力分量。为降低升力并最小化总流体动力载荷，本研究提出了一款新型标签设计（Model A，型号A），该设计集成了流体动力学优化的主体结构、用于平衡标签外壳上下侧流体速度差的导流通道，以及用于偏转流动以抵消升力的翼状结构。此外，本研究还基于型号A设计衍生出三款变体模型，用以探究各流动控制特征对整体性能的贡献。研究团队通过计算流体动力学（CFD）对四款模型的流体动力载荷开展了对比分析。型号A设计完全消除了升力，并在模拟的6 m/s顺流工况下产生了最高约30牛的向下作用力。本研究采用粒子图像测速法（PIV）对该标签设计周围的流场进行实验表征，以验证仿真结果的准确性。实验结果证实了仿真预测的流动趋势，并证明了流动控制元件在降低标签对动物产生的附加作用力方面具有潜在应用价值。