Theory Simulations and Experiments of Freak Waves
- Funded by:STW 7216
PhD:Arnida L. Latifah
Supervisor: Brenny van GroesenCollaboration:
'Freak waves' are waves of extreme, unexpectedly large height that suddenly appear in a relatively mild background wave field. Despite much research in the past two decades, not much is known yet about the mechanism that lead to their appearance, but reports about damages to ships caused by such waves increases. This research aims to explain the mechanism of a freak wave appearance. In this research we observe many types of wave groups which lead to a freak wave. One freak wave, of 18.5m crest height, has been recorded as a time signal from an oil platform in the North Sea called 'Draupner', and we use this information in our deterministic-stochastic investigations of freak waves, the so-called Draupner wave. In addition to the known 'NewWave' concept, we introduce 'maximal', and 'pseudo-maximal' waves as new concepts, and test the applicability. Numerical simulations with the AB equation provide additional insights in the spatial evolution of Draupner wave.
Both maximal and pseudo-maximal waves are coherent concepts and can model an extreme wave. This motivates us to investigate the description and the predictability of a freak event when at a certain position information in the form of a time signal is given. In the prediction of freak event, we used the phase information of the influx signal to estimate the position and the time of the occurrence of a large wave, and to predict the measure of phase coherence at the estimated focusing position. The coherence and the spectrum will determine an estimate for the amplitude. We applied these description and prediction of freak event in some cases, focusing signal, Draupner wave, and irregular waves. Meanwhile, we also did some experiments in generating large waves. One case of the experiments, the focusing signal is attached here.
- Freak waves Prediction in Irregular Waves Talks resentation at the JMBC Burgersdag, Eindhoven, January 2012 ·
- Investigations of coherence in Extreme water waves, presentation at the Open Research House, Labmath-Indonesia, January 2011 ·
- Investigations of coherence in Extreme water waves, presentation at the 13th Asian Congress of Fluid Mechanics 2010, Dhaka, Bangladesh
- Prediction of Extreme Waves using Phase Information, International Conference in Rogue waves, Dresden, 2011
- Investigation of coherence in freak waves, EGU Conference, Viena, April 201
PhD Defence on 13 October 2016
title: FREAK WAVE: Prediction and its Generation from Phase Coherence