An apparatus is described for the measurement of unsteady thrust and propulsive efficiency produced by biologically inspired oscillating hydrodynamic propulsors. Force measurement is achieved using a strain-gauge-based force transducer, augmented with a lever to amplify or attenuate the applied force and control the measurement sensitivity and natural frequency of vibration. The lever can be used to tune the system to a specific application and it is shown that, using the lever, the stiffness can be made to increase more rapidly than the measurement sensitivity decreases. Efficiency is computed from measurements of the time-averaged power imparted to the fluid. The apparatus is applied to two different propulsors, demonstrating the versatility of the system; wake visualizations are examined, which provide insight into the physical mechanisms of efficient propulsion.

中文翻译：

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使用新型测量系统的非定常推进器的推力性能和相应的尾流模式

描述了一种用于测量受生物启发的振荡水动力推进器产生的不稳定推力和推进效率的装置。力测量是使用基于应变计的力传感器实现的，通过杠杆增强以放大或衰减施加的力并控制测量灵敏度和振动的固有频率。杠杆可用于将系统调整到特定应用，结果表明，使用杠杆可以使刚度增加的速度比测量灵敏度降低的速度更快。效率是通过测量赋予流体的时间平均功率来计算的。该装置应用于两种不同的推进器，展示了系统的多功能性；检查唤醒可视化，