Sound radiation from rectangular plates vibrating in stripes mode.

Abstract

In this paper, the angle dependence of radiated sound pressure and radiation ratio are investigated in the frequency range of λ/λ_p&lt1 for the rectangular plates which vibrate in the stripes mode. They are calculated with introducing an angle component of the volume velocity at an elementary area on these plates whose angle component is determined by an angle between the rectangular plate and the plane containing the center axis parallel to the stripes and the observation point. The sound radiation from a surface of these plates is considered to be the radiation of sound from the bending waves in the plates which are propagated perpendicular to the stripes for the positive and negative directions. The radiation of sound from the bending wave in the one direction is approximated by the sound radiation from the rectangular piston which vibrates the maximum value of vibrational velocity of the bending waves, the dimensions of the rectangular piston are the same length of the parallel side to the stripes in width and √ &lt1-(λ/λ_p)^2&gt times the original side of the plates in length. The radiation ratio of these plates is expressed as √ &lt1-(λ/λ_p)^2&gt. The experimental results are in good agreement with the calculated ones.