Fan Z, Lowe M J S, Castaings M, Bacon C
Department of Mechanical Engineering, Imperial College, London SW7 2AZ, United Kingdom.
J Acoust Soc Am. 2008 Oct;124(4):2002-10. doi: 10.1121/1.2968677.
Guided torsional waves in a bar with a noncircular cross section have been exploited by previous researchers to measure the density of fluids. However, due to the complexity of the wave behavior in the noncircular cross-sectional shape, the previous theory can only provide an approximate prediction; thus the accuracy of the measurement has been compromised. In this paper, a semianalytical finite element method is developed to model accurately the propagation velocity and leakage of guided waves along an immersed waveguide with arbitrary noncircular cross section. An accurate inverse model is then provided to measure the density of the fluid by measuring the change of the torsional wave speed. Experimental results obtained with a rectangular bar in a range of fluids show very good agreement with the theoretical predictions. Finally, the potentials to use the model for sensor optimization are discussed.
先前的研究人员利用具有非圆形横截面的杆中的导波扭转波来测量流体的密度。然而，由于非圆形横截面形状中波行为的复杂性，先前的理论只能提供近似预测；因此测量的准确性受到了影响。在本文中，开发了一种半解析有限元方法，以精确模拟沿具有任意非圆形横截面的浸没波导的导波传播速度和泄漏。然后提供了一个精确的反模型，通过测量扭转波速度的变化来测量流体的密度。在一系列流体中使用矩形杆获得的实验结果与理论预测非常吻合。最后，讨论了使用该模型进行传感器优化的潜力。
