Abstract
Hydroacoustic particle motion may be detected by hot-film anemometry. Free convection causes a vertical flow that acts as a bias for vertical particle motion, resulting in a linear dependence of output voltage on the displacement. For horizontal particle motion, the output frequency is twice that of the acoustic field, and the output depends quadratically on the motion. An imposed bias flow increases the sensitivity and provides independence of the direction of gravity. The measurements are performed for water and ethylene glycol with sensors of diameters 25, 50, and 150 μm and temperature differences between sensor and medium of 15°, 30°, and 45 °C. The frequency range for horizontal motion is 20–160 Hz and for vertical motion is 20–500 Hz. The results are presented in terms of dependence of the ac Nusselt number as a function of relative displacement, Fourier number, and Rayleigh or Grashof number. At constant intensity, the output is inversely proportional to frequency to the 3/2 power for the horizontal case, and inversely proportional to the frequency for the vertical case.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
