Experimental investigation of scattering from randomly rough elastic cylinders
Gurley, John V.
MetadataShow full item record
Acoustical backscattering from randomly rough infinitely long elastic cylinders surrounded by a fluid medium is examined. The cylinder radius is allowed to vary along its lengthwise axis creating one-dimensional rotationally symmetric roughness. Using recently published rough cylinder formulations [T.K. Stanton, J. Acoust. Soc. Am., 92, 1641-1664 (1992) and T.K. Stanton and D. Chu, J. Acoust. Soc. Am., 92, 1665-1678 (1992)], explicit expressions are derived for the backscattered field for a laboratory pulse-echo environment: spherically spreading directional source and receiver with arbitrary beam patterns. Efficient numerical integration algorithms are developed to solve for the backscattered field from a specified surface profile. Experimental measurements from dense elastic (stainless steel) cylinders immersed in water are presented to quantitatively illustrate the effects of small scale surface roughness (δs/a = 0.0131 where δ is the surface rms roughness and a is the mean cylinder radius) for 4.5 < ka < 70 where k is the acoustic wavenumber. The actual target surface profile is well described and used as an input in the numerical simulations. Agreement is found between measurements and simulation predictions both in the mean field levels and the field fluctuations over a wide range of frequencies.
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992
Showing items related by title, author, creator and subject.
Bhatia, Saurav (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-08)The echo statistics of a randomly rough, randomly oriented prolate spheroid that is randomly located in a beampattern are investigated from physics-based principles both analytically and by Monte Carlo methods. This is ...
Broadband and statistical characterization of echoes from random scatterers : application to acoustic scattering by marine organisms Lee, Wu-Jung (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-02)The interpretation of echoes collected by active remote-sensing systems, such as sonar and radar, is often ambiguous due to the complexities in the scattering processes involving the scatterers, the environment, and the ...
Merab, Andre A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1987-01)This thesis presents the theoretical and computational underpinnings of a novel approach to the determination of the acoustic parameters of the ocean bottom using a monochromatic source. The problem is shown to be ...