Acoustic scattering from a finite spaced stiffeners: Experimental cylindrical shell with evenly investigation

摘要

The influence of evenly spaced ribs (internal rings) on the acoustic scattering from a finite cylindrical shell is examined over the dimensionless frequency range 1 < ka < 42 (where k is the wave number in water and a the outer radius of the cylinder). Experimental results, obtained with a monostatic setup, are discussed in the incidence angle/time and incidence angle/frequency domains. The physical phenomena that give rise to highlights in the experimental spectra (Bragg scattering and scattering from Bloch-Floquet waves) are investigated. Fast Fourier Transform (FFT) processing on different segments of time signals allows us to distinguish influences of these phenomena. Further, comparison is made between frequency based results and numerical results provided by, respectively, a theoretical model using the thin shell theory [Tran-Van-Nhieu, J. Acoust. Soc. Am. 110, 2858-2866 (2001)] and a simple scattering/interference calculation. (c) 2005 Acoustical Society of America.