Accession Number : AD1034376


Title :   Underwater Acoustic Carbon Nanotube Thermophone


Descriptive Note : Technical Report


Corporate Author : Naval Undersea Warfare Center Newport United States


Personal Author(s) : Howarth,Thomas R ; Huang,Dehua


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/1034376.pdf


Report Date : 23 Sep 2016


Pagination or Media Count : 10


Abstract : The present invention is an acoustically transparent carbon nanotube underwater acoustic source which acts as a thermophone based on an energy conversion of heat to sound. The principle of thermal acoustic transduction is thatwhen alternating current is passed through a comparatively thin transducer; periodic heating takes place in the conductor following variations in current strength. This periodic heating produces temperature waves which propagate into a surrounding medium. The amplitude of the temperature wave decreases rapidly as the distance from the conductor increases. Based on the rapid production of these temperature waves; the net effect is to produce a periodic rise in temperature in a limited portion of the medium near the conductor. Thermal expansion and contraction of this layer of the medium determines the amplitude of the resulting sound waves.


Descriptors :   carbon nanotubes , underwater acoustics , transducers , acoustic propagation , sound waves


Subject Categories : Acoustics
      Refractory Fibers


Distribution Statement : APPROVED FOR PUBLIC RELEASE