Random Wave Measurements in Front of Reflective Structures

Abstract

The changes in the wave spectrum and significant wave height near a reflective structure are investigated. Significant wave-height measurements with a one wave gauge show a standing wave pattern near the structure, extending offshore to about two times the spectral-peak wavelength for a JONSWAP incidental wave spectrum. The measured spectra also reveal a pattern of nodal and antinodal frequencies, even to much larger distances from the structure. These findings are in agreement with results from linear wave theory. Multigauge techniques can be used to discriminate between incident and reflected waves. Despite the standing wave pattern these techniques can be used to determine the incident wave height accurately up close to the structure—the distance being limited by the extend of the evanescent wave modes attached to the structure.