Development and Testing of an Acoustic System for 'in situ' Determination of Microbubble Concentrations in the Ocean.

Abstract

The effect of bubbles on sound propagation in the ocean has long been known. More recently, bubbles rising to the ocean surface have been related to salt nuclei in clouds. Yet due to the lack of suitable instrumentation little data are available on the concentration of bubbles in the ocean. A one-dimensional standing wave system was constructed and evaluated to determine bubble concentrations by measuring the effect of bubbles on the system damping constant 1/Q. The system was comprised of a mylar electrostatic transducer built into a plane reflector facing a parallel reflecting plate, and associated electronic components. The system was designed to measure bubbles of radius from approximately 500 microns to 30 microns utilizing frequencies from 20 to 100 kHz at depths to 30 meters. The system accuracy was determined to be plus or minus 10Hz in resonant bandwidth corresponding to 500 bubbles/cum at 67 kHz. The system was used to successfully measure bubbles in a laboratory tank. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1971
Accession Number
AD0728691

Entities

People

  • Leonard Arnold Wiens

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Accuracy
  • Bandwidth
  • Doppler Effect
  • Electronic Components
  • Frequency
  • Frequency Shift
  • Instrumentation
  • Reflectors
  • Standing Waves
  • Transducers
  • Waves

Readers

  • Acoustical Oceanography.
  • Aerospace Test and Evaluation
  • Underwater engineering and Marine Technology.

Technology Areas

  • Microelectronics
  • Microelectronics - Microelectromechanical Systems