Accession Number : AD0634546

Title :   ECHOES FROM HOLLOW ALUMINUM SPHERES IN WATER,

Corporate Author : CALIFORNIA INST OF TECH PASADENA DIV OF ENGINEERING AND APPLIED SCIENCE

Personal Author(s) : Diercks, K. Jerome ; Hickling,Robert

Report Date : MAR 1966

Pagination or Media Count : 42

Abstract : Recorded far-field echoes from precision hollow aluminum spheres in water, with different shell thicknesses and with either water or air in the hollow interior, are compared with calculated echoes. Steady state echoes are investigated over a range of ka from 6 to 27, and individual pulsed echoes at ka = 20. Excellent verification is obtained for the features predicted by the theory. It is shown that the echoes are sensitive to changes in the elastic properties of the shell, particularly when the shell is thin. The experiments showed moreover that the echoes are dependent on the orientation of the sphere. This is due presumably to asymmetries in the structure and properties of the shell and emphasizes again the strong interrelation between sonar echoes and the nature of the material in the target. (Author)

Descriptors :   (*ECHO RANGING, SONAR TARGETS), (*SONAR TARGETS, *SPHERES), (*ALUMINUM, SONAR TARGETS), SONAR, SOUND TRANSMISSION, UNDERWATER SOUND, ACOUSTICS

Subject Categories : Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE