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Flow-induced Vibration of Double Wall Carbon Nanotubes Conveying Pulsating Fluid.

Alnujaie, Ali H
http://orcid.org/0000-0002-5771-7227
http://rave.ohiolink.edu/etdc/view?acc_num=akron1555409894074253

Abstract Details

2019, Doctor of Philosophy, University of Akron, Engineering.
Flow-induced vibrations of double-walled carbon nanotubes are examined using Euler Bernoulli beam models. The problem formulation, governing differential equation and dimensionless frequency response for double-walled nanotubes are different because of the presence of The van der Waals forces. The potential energy of vdW forces is linearized, and its effect is modeled a linear spring. DWCNT with fixed-fixed and fixed-free (cantilevered) are selected in this work. The system response of DWCNT conveying fluid with constant flow and neglected gravity was studied via an analytical method. Also, Galerkin's method is adopted to investigate the dynamical behavior of DWCNT carrying a continuous fluid flow with considered gravity. A parametric instability is induced if the fluid is pulsating. Primary and secondary parametric instabilities of double wall carbon nanotubes (DWCNT) are fundamental to investigate. Therefore, Bolotin's method is accompanied by Galerkin's method to examine the parametric instability of the system having pulsating fluid flow. When the fluid flow is constant, buckling (divergence) and flutter are two instabilities of concern. The results of the first two approaches show that gravity has a negligible effect on the system dynamical behavior at (u=1). Also, the results prove that a fixed-fixed tube is more stable when the fluid flow is constant. The first mode divergence takes place at (u=14.3) while fixed-free tubes lose stability by second mode flutter at (u=11.45). When fluid flow is pulsating, the primary parametric resonances occur for the first three modes of fixed-fixed DWCNT whereas secondary v parametric resonances have a trivial effect on the system stability at low fluid velocity (1). Likewise, the non-coaxial mode shapes resonances are negligible at the same fluid velocity. On the other hand, the first axial and non-coaxial modes of fixed-free tubes have a minimal effect on the system response of both types of parametric instability. However, the system is unstable at the second, third and fourth axial and non-coaxial modes. A parametric study is conducted in chapter 5 showing the effect of mass ratio, fluid velocity, and gravity. Both mass ratio and fluid velocity decrease system stability as they increase. Gravity has a stabilizing effect on system performance. Finally, the result from the finite element method is compared to the previous one and shows a great match.
Graham Kelly, PhD (Advisor)
Gao Xiaosheng , PhD (Committee Member)
Buldum Alper, PhD (Committee Member)
Sozer Yilmaz , PhD (Committee Member)
Kreider Kevin , PhD (Committee Member)
177 p.
Mechanical Engineering
Flow-induced; vibration; Double wall carbon nanotube; Bolotin method; primary instability; secondary instability

Recommended Citations

Citations

  • Alnujaie, A. H. (2019). Flow-induced Vibration of Double Wall Carbon Nanotubes Conveying Pulsating Fluid. [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555409894074253

    APA Style (7th edition)

  • Alnujaie, Ali. Flow-induced Vibration of Double Wall Carbon Nanotubes Conveying Pulsating Fluid. 2019. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1555409894074253.

    MLA Style (8th edition)

  • Alnujaie, Ali. "Flow-induced Vibration of Double Wall Carbon Nanotubes Conveying Pulsating Fluid." Doctoral dissertation, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555409894074253

    Chicago Manual of Style (17th edition)

akron1555409894074253
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© 2019, some rights reserved.Creative Commons License Flow-induced Vibration of Double Wall Carbon Nanotubes Conveying Pulsating Fluid. by Ali H Alnujaie is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Akron and OhioLINK.