Axisymmetric Wave Propagation Behavior in Fluid-Conveying Carbon Nanotubes Based on Nonlocal Fluid Dynamics and Nonlocal Strain Gradient Theory

Yang Yang,Rongxin Guo,Qihui Lin

doi:10.1007/s42417-019-00194-1

Yang Yang, Rongxin Guo + Show 1 more

Open Access

https://doi.org/10.1007/s42417-019-00194-1

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Abstract

PurposeGoal 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.MethodAn 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.ResultsThe 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 second-mode 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.

Highlights

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
molecular dynamics simulations (MD) is the most reasonable approach because it calculates the interaction between all of the atoms in the system, but the application of MD is limited to some complex structures, such as fluid-conveying systems
Some dynamic properties predicted by classical models are inaccurate since the size effects at nanoand microscales are ignored

Summary

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. Keywords Nonlocal fluid dynamics · Nonlocal strain gradient theory · Fluid-conveying carbon nanotubes · Axisymmetric wave propagation · Elastic shell model The nonlocal constitutive equation can only predict the scale effects of solids, when fluid flow inside CNT must be modeled by other theories, such as the slip boundary theory [14,15,16].

Results

Conclusion