Comparison Study of Experiments and Predictions of Wave Kinematics for Rogue Wave

Abstract

SummaryTo investigate the wave kinematics under the rogue wave crest, a series of experiments were performed in 2-D wave tank with the application of PIV technique to measure the velocities under the free surface. Three different prediction methods of linear extrapolation, Wheeler stretching, and modified stretching were applied to estimate water wave kinematics and compared with PIV experimental results under the highest wave crest of irregular wave trains satisfying with rogue wave criteria. Also, the cut-off frequency dependence for three prediction methods was investigated with varying spectral peak frequencies to estimate wave kinematics including velocities and accelerations in horizontal and vertical directions. It was suggested that the cut-off frequency for the reasonable prediction of the wave kinematics under the rogue wave crest could be chosen three times of spectral peak wave frequency for the linear extrapolation and higher frequency than four times of spectral peak wave frequency for Wheeler stretching and modified stretching method.

Assessing the validity of regular wave theory in a short physical wave flume using particle image velocimetry

“…The comparison of wave theory to measurements of the fluid velocity in a physical wave tank has been performed for a range of scenarios, such as: bichromatic waves [20,21], irregular waves [22][23][24][25][26], extreme waves/focused waves [27][28][29][30][31][32][33], internal waves [34][35][36] and the investigatioon of the higher order drift effects [37][38][39][40][41]. Considering the fundamental case of regular waves, several studies can be found in the literature performing experimental measurements of the wave kinematics and comparing the results to wave theories.…”

“…As part of their PIV investigation into the kinematics of rogue waves Choi et al [33,48] and Jung et al [32] also perform tests of a large regular wave for comparison. unlike the majority of other studies, the quality of the incoming wave field is quantified, providing the root-mean-square error between the wave height of consecutive wave periods and the mean wave height.…”

“…The motivation for specifically considering a short wave flume is to enable the applicability of the results to practical wave tank testing situations, in which the finite length of the tank has a non-negligible effect on the wave kinematics. While several studies have investigated the ability of wave theory to describe the wave kinematics measured in a physical wave tank, they have done so under ideal conditions, performing the measurements close to the wave maker, utilising a long enough wave tank and short enough time window to eliminate the effect of reflections [33,48,49].…”