Remote acoustic illumination using time reversal and a surface ship.

Area of Science:

• Acoustics
• Wave Propagation
• Signal Processing

Background:

• Time-reversal (TR) transmission in acoustic waveguides enables spatio-temporal focusing.
• TR focuses can act as virtual point sources, enabling remote acoustic field manipulation.
• Virtual source arrays (VSAs) can redirect focused fields, but practical implementation is challenging.

Purpose of the Study:

• To propose and demonstrate a novel method for creating a horizontal virtual source array (VSA) using a surface ship and time-reversal mirror (TRM).
• To overcome the limitation of requiring multiple probe sources for VSA implementation.
• To enable remote acoustic illumination in shallow water environments where Green's functions are not readily available.

Main Methods:

• Utilizing time-reversal (TR) transmission of the Green's function between a TRM and a probe source (PS).
• Employing a surface ship radiating broadband noise as a PS.
• Integrating waveguide invariant theory to generate a horizontal VSA instantly.
• Conducting numerical simulations in shallow water to validate the approach.

Main Results:

• Demonstrated the creation of a virtual point source from a TR focus.
• Showcased the potential for multiple TR focuses to form a VSA.
• Successfully simulated the generation of a horizontal VSA using a ship and TRM.
• Validated the feasibility of remote acoustic illumination using this method in shallow water.

Conclusions:

• A surface ship radiating broadband noise can serve as a probe source for generating a VSA.
• The proposed method offers a practical solution for remote acoustic illumination.
• This technique holds promise for applications in shallow water acoustics and underwater communication.