Comments on “Flexural wave reduction using a compliant tube baffle” [J. Acoust. Soc. Am. 99(2), 691–699 (1996)] and “Signal pressure received by a hydrophone placed on a plate backed by a compliant baffle” [J. Acoust. Soc. Am. 89(2), 559–564 (1991)

Abstract

The cited formulations for studying the baffling of flexural waves by a compliant tube grating [S. H. Ko, J. Acoust. Soc. Am. 99, 691–699 (1996)] and for determining the acoustic receive sensitivity of a hydrophone placed near a plate backed by a compliant tube grating [S. H. Ko and H. H. Schloemer, J. Acoust. Soc. Am. 89, 559–564 (1991)] are dependent on the validity of the lumped-fluid parameter approximations developed by Junger [M. C. Junger, J. Acoust. Soc. Am. 78, 1010–1012 (1985)] for a grating of closely spaced compliant tubes between two semi-infinite fluid half-spaces. If the fluid between the plate and the grating is great enough to minimize their interaction, the incorporation of the effective layer parameters developed by Junger should be reasonably valid. Unfortunately, the sample calculations in Ko (Ref. 4) and Ko and Schloemer (Ref. 5) have been made for the limiting case of the compliant tube grating in direct contact with the plates where the use of Junger’s approximations is inappropriate.