A STUDY OF THE SCATTERING OF SOUND WAVES IN FLUIDS. PART 2. INFLUENCE OF SUBMARINE HULLS ON SOUND INTENSITY MEASUREMENTS

Light waves are too short and ordinary sound waves generally too long to permit experimental work on diffraction and scattering by a single small obstacle. An opportunity for such work however is presented in the case of ultrasonic waves.This paper describes an experimental investigation on the factors which determine the diffractive reflection and scattering of an ultrasonic wave train by plane circular opaque discs, and discusses the results. These are of special importance in the measurement of sound energy intensity by the torsion-pendulum method, for such measurements should always be corrected to allow for the effect of diffractive scattering of the energy by the measuring-pendulum vane. The correction factor will depend on the size and form of the pendula vanes employed and for circular vanes can be obtained directly from such curves as are shown in this paper as results of the investigation.

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Avoiding pitfalls in mastering sound intensity measurements

The Journal of the Acoustical Society of America ◽

10.1121/1.2026265 ◽

1988 ◽

Vol 84 (S1) ◽

pp. S31-S31

Author(s):

Frank H. Brittain

Keyword(s):

Sound Intensity ◽

Intensity Measurements

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New Toothed Belt Matches Various Pulley-Profiles

Volume 6: 8th International Power Transmission and Gearing Conference ◽

10.1115/detc2000/ptg-14410 ◽

2000 ◽

Author(s):

Frank H. Schaefer

Keyword(s):

Sound Intensity ◽

Belt Drive ◽

Special Test ◽

Intensity Measurements ◽

Test Conditions ◽

Toothed Belt ◽

Quality Of Motion ◽

Center Distance ◽

Dynamometer Test

Abstract This paper examines the possibility of a new toothed belt construction to run in various pulley-types. The measurements from a laboratory dynamometer test stand show the belt life under special test conditions by use of HTD-, STPD- and RPP-pulleys, each with an angle of wrap of 180°. In case of locked center distance the increase of torque causes tooth climbing until belt jumping occurs. The pretension was brought into line with the torque each time the torque was increased and the jumping limit torque was determined. From literature it is expected that the results for the behavior of the HTD- and the RPP-pulley are similar. Another parameter to describe the quality of motion is the noise. Here sound power is a very effective descriptor of how noisy an object is. It was determined from sound intensity measurements for HTD- and STPD-pulleys. The ratio of the toothed belt drive used for the noise measurement was 0.63.

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