We propose the design of a tubular phononic crystal (TPC) for the purpose of sensing the physical properties of a liquid filling the hollow part of the tube. The TPC is constituted by a periodic repetition of washers along a hollow pipe with the advantage of avoiding any perturbation of a flowing fluid by any element inside the tube. Using finite element simulations, we demonstrate the existence of complete as well as polarization dependent bandgaps inside which one can design localized modes associated with defects. The most sensitive cavity to the liquid sound velocity is found to be constituted by a Fabry–Pérot (F–P) cavity. The signature of the cavity modes can be detected as peaks or dips in the transmission spectrum as well as at the external surface of the cavity. We study the dramatic effect of the liquid viscosity, more particularly shear viscosity, on these features and discuss the conditions for their practical observation. A TPC test sample made of a polymer is fabricated by means of 3D printing and characterized without the liquid by transmission measurements. The comparison with the simulations showed the necessity of considering the damping of the polymer whose effect on the transmission features is discussed. Our sensor design can find many applications at different scales in several systems transporting a fluid as microfluidic channels in micro- and nanotechnologies, syringes in medicine, or pipelines in civil engineering.

中文翻译：

---

管状声子晶体传感器

我们提出了管状声子晶体 (TPC) 的设计，目的是感测填充管中空部分的液体的物理特性。TPC 由沿中空管周期性重复的垫圈构成，其优点是避免了管内任何元件对流动流体的任何扰动。使用有限元模拟，我们证明了完整的以及偏振相关的带隙的存在，可以在其中设计与缺陷相关的局部模式。发现对液体声速最敏感的腔由法布里-珀罗 (F-P) 腔构成。腔模式的特征可以被检测为透射光谱中以及腔外表面的峰或谷。我们研究了液体粘度的巨大影响，更特别的是剪切粘度，关于这些特征并讨论它们实际观察的条件。由聚合物制成的 TPC 测试样品通过 3D 打印制造，并通过透射测量表征不含液体。与模拟的比较表明，有必要考虑聚合物的阻尼，讨论其对传输特性的影响。我们的传感器设计可以在多个系统中找到不同规模的许多应用，这些系统将流体作为微和纳米技术中的微流体通道、医学中的注射器或土木工程中的管道。与模拟的比较表明，有必要考虑聚合物的阻尼，讨论其对传输特性的影响。我们的传感器设计可以在多个系统中找到不同规模的许多应用，这些系统将流体作为微和纳米技术中的微流体通道、医学中的注射器或土木工程中的管道。与模拟的比较表明，有必要考虑聚合物的阻尼，讨论其对传输特性的影响。我们的传感器设计可以在多个系统中找到不同规模的许多应用，这些系统将流体作为微和纳米技术中的微流体通道、医学中的注射器或土木工程中的管道。