Axisymmetric Wave Propagation Behavior in Fluid-Conveying Carbon Nanotubes Based on Nonlocal Fluid Dynamics and Nonlocal
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REVIEW
Axisymmetric Wave Propagation Behavior in Fluid‑Conveying Carbon Nanotubes Based on Nonlocal Fluid Dynamics and Nonlocal Strain Gradient Theory Yang Yang1 · Qihui Lin1 · Rongxin Guo1 Received: 31 October 2019 / Revised: 20 December 2019 / Accepted: 23 December 2019 © The Author(s) 2020
Abstract Purpose Goal for the present research is investigating the axisymmetric wave propagation behaviors of fluid-filled carbon nanotubes (CNTs) with low slenderness ratios when the nanoscale effects contributed by CNT and fluid flow are considered together. Method An elastic shell model for fluid-conveying CNTs is established based on theory of nonlocal elasticity and nonlocal fluid dynamics. The effects of stress non-locality and strain gradient at nanoscale are simulated by applying nonlocal stress and strain gradient theories to CNTs and nonlocal fluid dynamics to fluid flow inside the CNTs, respectively. The equilibrium equations of axisymmetric wave motion in fluid-conveying CNTs are derived. By solving the governing equations, the relationships between wave frequency and all small-scale parameters, as well as the effects caused by fluid flow on different wave modes, are analyzed. Results The numerical simulation indicates that nonlocal stress effects damp first-mode waves but promote propagation of second-mode waves. The strain gradient effect promotes propagation of first-mode waves but has no influence on secondmode waves. The nonlocal fluid effect only causes damping of second-mode waves and has no influence on first-mode waves. Damping caused by nonlocal effects are most affect on waves with short wavelength, and the effect induced by strain gradient almost promotes the propagation of wave with all wavelengths. Keywords Nonlocal fluid dynamics · Nonlocal strain gradient theory · Fluid-conveying carbon nanotubes · Axisymmetric wave propagation · Elastic shell model
Introduction Since the development of application about micro/nano-electro-mechanical systems (M/NEMS) in chemical, medicine and mechanical engineering, fluid transmission at microand nanotubes or channels attracts lots of research interests. The key factor for the design and production of such fluid transmission structures is the fluid–structure interaction at the micro- or nanoscale, especially the dynamic behavior for fluid-conveying CNTs [1–3].
* Yang Yang yangyang0416@kust.edu.cn 1
Key Laboratory in Yunnan Province for Disaster Reduction of Civil Engineering, Kunming University of Science and Technology, Kunming 650500, China
Theoretical analysis and experimental research are two general approaches for studying the dynamic characteristics of fluid-conveying CNTs. However, dynamic experimentation at the nanoscale is quite difficult to execute and control [2]; many theoretical and numerical methods have been employed, including molecular dynamics simulations (MD) [4, 5], classical elastic constitutive models [6], and smallscale elastic models such as the coupled stress model, nonlocal elastic model and elastic strain gradient model [7–16
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