Measurement of added mass for an object oscillating in viscous fluids using nonlinear self-excited oscillations
Measurement of added mass for an object oscillating in viscous fluids using nonlinear self-excited oscillations
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DOI：
10.1007/s11071-020-06087-3
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发表时间：
2020-11
影响因子：
5.6
通讯作者：
Jiahao Yang;H. Yabuno;Naoki Yanagisawa;Yasuyuki Yamamoto;S. Matsumoto
中科院分区：
文献类型：
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作者：
Jiahao Yang;H. Yabuno;Naoki Yanagisawa;Yasuyuki Yamamoto;S. Matsumoto
在这项研究中，一种方法来测量的附加质量的物体在粘性流体中振荡使用非线性自激振荡。增加的质量对振动的物体产生额外的惯性效应。在以前的方法中，附加质量是根据在谐波强迫激励下的频率响应曲线中的峰值处的响应频率和振幅通过实验获得的。然而，这种方法不能在高粘性环境中使用，因为峰值由于阻尼而变得模糊。此外，在非常高粘度的环境中，共振峰不再存在于频率响应曲线中。为了解决这个问题，自激振荡诱导系统中使用线速度反馈。因为当线性反馈增益设置在与自激振荡相关的Hopf分叉点附近时，线性速度反馈可以用于消除粘性阻尼效应，所以物体在等于物体在真空中振荡的固有频率的频率下变得自激，即，无阻尼自然频率。该方法与上述先前方法的区别在于不需要响应值;但是，需要降低振幅才能获得准确的测量结果。在所提出的方法中，以避免在施加线性速度反馈下的响应幅度的增加，非线性反馈也施加到产生一个极限环类似于产生在一个货车der Pol振荡器。基于所提出的方法构建了测量系统的原型。实验和理论获得的附加质量值的比较证实了所提出的方法的有效性，为附加质量传感。
In this study, a method of measuring the added mass for an object oscillating in a viscous fluid using nonlinear self-excited oscillations was developed. The added mass produces an additional inertial effect on the vibrating object. In previous methods, the added mass is obtained experimentally from the response frequency and amplitude at the peak in the frequency response curve under a harmonically forced excitation. However, such methods cannot be utilized in highly viscous environments because the peak becomes ambiguous as a result of damping. Moreover, in very high-viscosity environments, the resonance peak ceases to exist in the frequency response curves. To solve this problem, self-excited oscillations were induced in the system using linear velocity feedback. Because linear velocity feedback can be used to eliminate the viscous damping effect when the linear feedback gain is set near the Hopf bifurcation point related to self-excited oscillations, the object becomes self-excited at a frequency equal to the natural frequency of the object oscillating in a vacuum, i.e., the undamped natural frequency. What distinguishes the proposed method from the abovementioned previous methods is that the value of the response is not needed; however, a reduction in the oscillation amplitude is required to obtain accurate measurement results. In the proposed method, to avoid an increase in the response amplitude under the applied linear velocity feedback, nonlinear feedback is also applied to produce a limit cycle similar to that produced in a van der Pol oscillator. A prototype of the measurement system was constructed based on the proposed method. A comparison of the experimentally and theoretically obtained added mass values confirmed the validity of the proposed method for added mass sensing.