Abstract:
A preliminary investigation using cold water from melting ice to induce sound-speed fluctuations has shown significant effects on both one-way and two-way propagation. Although the melting ice approach is simple and effective, it is not easily controlled. The purpose of the present research is to develop a method for generating controlled sound-speed fluctuations by creating a thermal field with stable and repeatable statistics. The work has led to a novel cold water injection system for generating thermal fluctuations in an experimental tank. A relatively simple device has been designed for producing a range of turbulence spectra by varying the flow rate and orifice sizes. This paper will focus on the characteristics of the cold water injection system and will discuss its advantages over systems that use, for example, electric heaters or hot water injection to create the thermal fluctuations. Results from preliminary acoustic tests will be discussed. [Work supported by the Office of Naval Research and the Applied Research Laboratory.]