EXTENDING LOW-FREQUENCY TRAVELING-WAVE PROPAGATION IN A WATER-FILLED CYLINDRICAL WAVEGUIDE USING ACTIVE IMPEDANCE CONTROL

Author

• William Slater, University of Rhode IslandFollow

Date of Award

2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Ocean Engineering

Department

Ocean Engineering

First Advisor

James Miller

Abstract

This dissertation investigates extending the frequency range over which a one-dimensional, plane traveling wave can be generated in a water-filled, steel-walled waveguide under ocean temperature and hydrostatic pressure conditions. The wave guide considered is a thick-walled, steel cylinder filled with a water/glycol mixture with a transducer at each end and a hydrophone array along the length. One transducer excites a plane wave while the other cancels reflections, resulting in a traveling wave in the waveguide. The current (open-loop) measurement system is advertised to generate traveling waves for low frequencies where only 3.4% of a wavelength can be measured (kL of 0.07p where L is the hydrophone array length). An analytical and finite element analysis of the waveguide illustrates the fluid-elastic propagation properties necessary to understand the accuracy of the plane wave assumption. Study of the multi-point impedance measurement method reveals the limitations of the measurement system in accurately producing plane traveling waves. After creation of a new, closed-loop measurement system, plane traveling waves were generated for frequencies where only 0.34% to 1.4% of a wavelength could be measured (kL of 0.01p to 0.03p). An upper frequency limit at kD = p/2, where D is the waveguide diameter, is necessary to avoid non-planar propagating modes. Within this frequency range, and in the absence of the L₀₂ (ET1) mode, the uncertainty of the traveling wave amplitude is £ 0.7 dB as shown by a Monte Carlo analysis. With the extended range, the measurement system provides nearly the full frequency coverage specified for relevant calibration standards, IEC 60565-1:2020 and IEC 63305:2024.

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Recommended Citation

Slater, William, "EXTENDING LOW-FREQUENCY TRAVELING-WAVE PROPAGATION IN A WATER-FILLED CYLINDRICAL WAVEGUIDE USING ACTIVE IMPEDANCE CONTROL" (2026). Open Access Dissertations. Paper 4562.
https://digitalcommons.uri.edu/oa_diss/4562