Determination of sediments diameter using acoustic waves

Document Type: physical oceanography

Authors

1 Department of Physical Oceanography, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Environmental Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

3 Department of Marine Industry, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract

The use of acoustic waves in researches related to sea water is of most importance among scientists recently. Since these waves are the only waves, transmitted in water with lowest attenuation and high speed, they can be used in many scientific fields. The main goal of this research is to better understand the physics and mechanisms of sound-seabed interaction, including acoustic penetration, propagation, attenuation and scattering in marine sediments using a laboratory study approach. Sound backscattering from water sediments at central frequencies 1,2.25,5,10 and 15 MHz was studied in controlled laboratory conditions. Six kinds of sediments, from very coarse sands to fine sands, were degassed, and their surface was flattened. In these conditions, the sediment granular structure can be considered as the only controlling mechanism of backscattering. Comparison of frequency dependencies of backscatter for the six sediments with different mean grain sizes shows that in which frequencies we have the maximum backscattering sensitivity to the sediment mean grain diameter, and frequency-dependent attenuation will be shown.

Keywords