Measurements of particle velocities in laboratory-scale random waves

Abstract

The paper describes measurements of water particle velocities in laboratory-scale irregular, non-periodic surface waves. The measurements were taken over a range of elevations using Laser Doppler anemometry and included observations of particle kinematics at two points separated in plan. The observed statistical and spectral properties were compared with those predicted by both traditional and intermittent linear random wave theory. For elevations which are always submerged, the measured properties were in good agreement with both theoretical approaches. This was not the case for points near mean water level, where the observed properties were approximated more closely by the intermittent approach. However, some departure between observations and the intermittent approach was evident for elevations above mean water level.