Experimental Study of the Scattering of Acoustic Energy from Solid Metal Spheres in Water

Abstract

An experimental study of the scattering of acoustic energy from solid metal spheres in water has been carried out in the frequency range 50–150 kc and with a range of sphere sizes from 1 to 7 in. in diam, giving values of ka (acoustic radius) from 4.1 to 57. Data are presented which show the scattered pulse formation for pulses which are short compared to the sphere and for pulses which are long compared to the sphere as a function of frequency, of scattering angle, and of sphere composition. The study shows that the spheres cannot be treated as rigid bodies since an appreciable amount of energy penetrates the surface and results in a complicated echo structure for the scattered signal. The back-scattered target strength of spheres for short pulses (and considering only the surface-reflected pulse) is essentially constant with frequency for large ka, and is slightly less than the theoretical value for rigid spheres. For pulses which are long compared to the transit time across the sphere, the target strength fluctuates as much as 30 db for small changes in frequency. For short pulses the angular distribution of the scattered energy is fairly uniform over the back 180°, but this is not true for long pulses.

<title>Target shape and material composition from resonance echoes of submerged elongated elastic targets</title>

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Creeping-Wave Analysis of Acoustic Scattering by Elastic, Cylindrical Shells

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Modeling analysis of ultrasonic attenuation and angular scattering measurements of suspended particles

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