Theory of suspended carbon nanotube thinfilm as a thermal-acoustic source

Accurate analytical solutions for thermal-acoustic radiation from a suspended carbon nanotube (CNT) thinfilm is obtained for near- and far-fields by constructing a coupled thermal-mechanical CNT model and solving for the thermally induced acoustic response. The analytical approximate acoustic pressure is expressed in a brief and concise form after proper approximation within a certain frequency range. An example using CNT-thinfilm is presented and compared with experimental measurement in order to verify the theoretical model and analytical prediction. It is concluded that the approximate analytical solution obtained agrees well with experimental results. The heat capacity per unit area significantly influences the acoustic pressure and a CNT-thinfilm with a small heat capacity per unit area improves acoustic pressure. Acoustic wave radiating from a CNT-thinfilm is a plane wave in a near-field and it transforms into a spherical wave in a far-field. Acoustic wave at higher frequency remains as a plane wave for a longer distance. In addition, it is concluded that acoustic pressure undergoes a wideband constant (flat) amplitude-frequency response in a near-field. (C) 2013 Elsevier Ltd. All rights reserved.