Natural Frequency and Stability Tuning of Cantilevered CNTs Conveying Fluid in Magnetic Field
This paper investigates the dynamics of cantilevered CNTs conveying fluid in longitudinal magnetic field and presents the possibility of controlling/tuning the stability of the CNT system with the aid of magnetic field. The slender CNT is treated as an Euler-Bernoulli beam. Based on nonlocal elasticity theory, the equation of motion with consideration of magnetic field effect is developed. This partial differential equation is then discretized using the differential quadrature method (DQM). Numerical results show that the nonlocal small-scale parameter makes the fluid-conveying CNT more flexible and can shift the unstable mode in which flutter instability occurs first at sufficiently high flow velocity from one to another. More importantly, the addition of a longitudinal magnetic field leads to much richer dynamical behaviors of the CNT system. Indeed, the presence of longitudinal magnetic field can significantly affect the evolution of natural frequency of the dynamical system when the flow velocity is successively increased. With increasing magnetic field parameter, it is shown that the CNT system behaves stiffer and hence the critical flow velocity becomes higher. It is of particular interest that when the magnetic field parameter is equal to or larger than the flow velocity, the cantilevered CNT conveying fluid becomes unconditionally stable, indicating that the dynamic stability of the system can be controlled due to the presence of a longitudinal magnetic field.
Key WordsCNT conveying fluid dynamics frequency stability magnetic field
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- 13.Lee, H. and Chang, W., Vibration analysis of fluid-conveying double-walled carbon nanotubes based on nonlocal elastic theory. Journal of Physics: Condersed Matter, 2009, 21: 115302.Google Scholar
- 22.Ansari, R., Gholami, R., Norouzzadeh, A. and Darabi, M.A., Surface stress effect on the vibration and instability of nanoscale pipes conveying fluid based on a size-dependent Timoshenko beam model. Acta Mechanica Sinica, 2015, DOI 10.1007/s10409-015-0435-4.Google Scholar
- 35.Kuang, Y.D., Shi, S.Q., Chan, P.K.L. and Chen, C.Y., A continuum model of the van der Waals interface for determining the critical diameter of nanopumps and its application to analysis of the vibration and stability of nanopump systems. International Journal of Nonlinear Sciences and Numerical Simulation, 2009, 10: 1563–1575.Google Scholar
- 39.Paidoussis, M.P., Fluid–Structure Interactions: Slender Structures and Axial Flow. Vol. 1, Academic Press Limited, London, 1998.Google Scholar