Dynamic wave measurement with a high spatial resolution distributed fiber optic pressure sensor

Wave assessment is essential for the design and monitoring of coastal structures, assisting engineers to ensure infrastructure integrity. Common methods for wave monitoring involve measuring water surface height or hydrostatic pressure, with pressure-based systems offering significant advantages, especially in the detection of small wave heights such as tsunamis in open ocean conditions. Distributed fiber optic (DFO) technology has played a key role in addressing complex engineering challenges by providing spatially high and accurate temperature and strain measurements. Recently, a distributed fiber optic pressure sensor (DPS) has been developed that can measure hydrostatic pressure with high spatial resolution and over long distances. This study assesses the dynamic wave measurement capability of the DPS by testing its ability to measure the hydrostatic pressure of a propagating solitary wave under controlled laboratory conditions. The DPS was tested with different relative wave heights and validated by two independent conventional measurement systems: 1) ultrasonic distance sensors (UDS) and 2) piezoresistive pressure sensors (PPS). The free water surface profile wave was reconstructed from the DPS and PPS pressure measurements using the Bonneton water surface reconstruction method. Comparison of the three measurement systems shows good agreement in detecting the target wave crests, with deviations of less than 3%. The proposed measuring system has great potential to be adopted as monitoring tool for wave-related field applications, such as coastal/surf zone monitoring or tsunami early warning systems, where high-resolution pressure measurements are required. However, additional field validations are needed to further assess its effectiveness under real-world conditions.