Nonlocal electro-thermal transverse vibration of embedded fluid-conveying DWBNNTs

Electro-thermal transverse vibration of fluid-conveying double-walled boron nitride nanotubes (DWBNNTs) embedded in an elastic medium such as polyvinylidene fluoride (PVDF) which is a piezoelectric polymer is investigated. The elastic medium is simulated as a spring and van der Waals (vdW) forces between inner and outer nanotubes are also taken into account. Zigzag structure of boron nitride nanotubes (BNNTs) is described based on the nonlocal continuum piezoelasticity cylindrical shell theory, and Hamilton's principle is employed to derive the corresponding higher-order equations of motion. In this model, DWBNNTs are placed in uniform temperature and electric field, the latter being applied through attached electrodes at both ends. Having considered the small scale effect, aspect ratio (L/R), densities of fluid and elastic medium, four different cases of loading are assumed in this study, including: a) direct voltage and heating (DVH), b) direct voltage and cooling (DVC), c) reverse voltage and heating (RVH), and d) reverse voltage and cooling (RVC). Numerical results indicate that increasing nonlocal parameter (e(0)a), for the four above mentioned cases, decreases the critical flow velocity of fluid. The results could be used in design of nano-electro-mechanical devices for measuring density of a fluid such as blood flowing through such nanotubes with great applications in medical fields.