Instabilities of SWCNT conveying laminar, incompressible and viscous fluid flow

Abstract

Purpose This study aims to study the transverse vibration and instabilities of the fluid-conveying single-walled carbon nanotubes (CNTs). To this purpose, the Euler–Bernoulli beam model is used. Also, the surface effects, small-size effects of the both fluid and structure and two different elastic mediums viscoelastic and Pasternak elastic are investigated. Design/methodology/approach To consider the nano-scale for the CNT, the strain-inertia gradient theory is used and to solve the governing equation of motion for the system, the Galerkin’s method is used. The effect of the flow velocity, aspect ratio, characteristic lengths of the mentioned theory, effects of Knudsen number and effects of the Winkler, the Pasternak elastic and the viscoelastic medium on the frequencies and stabilities of the system are studied. The effects of the above parameters on the vibrational behavior are investigated both separately and simultaneously. Findings The results show that the critical flow velocity value is increased as the aspect ratio, characteristic lengths, Winkler modulus, shear and damping factors increase. Also, the critical flow velocity is increased by considering the surface effects. In addition, the consequence of increase in the nano-flow-size effects (Knudsen number) is decreasing the critical flow velocity. Moreover, it can be observed that the effect of the shear factor on increasing the critical flow velocity is different from the rest of parameters. Originality/value Use of Timoshenko and modified couple stress theories and taking into account Von-Karman expressions for investigating the nonlinear vibrations of triple-walled CNTs buried within Pasternak foundation.

Investigation of viscous fluid flow and dynamic stability of CNTs subjected to axial harmonic load coupled using Bolotin’s method

“…By increasing the radius-to-length ratio, the DIR shifts to higher dimensionless excitation frequencies, and the unstable region becomes smaller. The extension of this paper for viscous fluid flow according to previous works (Mirkalantari et al, 2017;Saffari et al, 2017;Foroutan et al, 2018;Oveissi et al, 2016aOveissi et al, , 2016bOveissi and Ghassemi, 2018;Oveissi et al, , 2017Oveissi et al, , 2019Mohamadi et al, 2019) affords engineers a good option for fluid flow simulation. ) where:…”

“…The extension of this paper for viscous fluid flow according to previous works (Mirkalantari et al , 2017; Saffari et al , 2017; Foroutan et al , 2018; Oveissi et al , 2016a, 2016b; Oveissi and Ghassemi, 2018; Oveissi et al , 2018, 2017, 2019; Mohamadi et al , 2019) affords engineers a good option for fluid flow simulation.…”

Analytical determination of non-local parameter value to investigate the axial buckling of nanoshells affected by the passing nanofluids and their velocities considering various modified cylindrical shell theories

“…On the other hand, one of the topics discussed for practical applications is the behavior of systems with nano-fluidstructural interaction such as fluid conveying CNTs. [15][16][17][18] Size, condition of nano-materials, and nature of atomic bonds can affect the properties of the materials and systems. So far, many studies have shown the inaccuracy of classical theories, and it has been proved that very small-scale structures have different mechanical behavior, and they are length-scale dependent parameters.…”