Joint time-frequency properties of freak waves

Taekhyun Kim, Yong June Shin, Edward J. Powers, Nungsoo Kim, Cheung Hun Kim

Research output: Contribution to journalConference article

Abstract

In this paper, we discuss the joint time-frequency properties of a transient freak wave in order to distinguish the freak wave from non-freak waves in a quantitative manner. Exploring the use of an alternative to wavelet-based approaches, joint time-frequency distributions (TFDs), we portray the simultaneous time- and frequency-localized nature of freak waves vs. that of non-freak waves. The knowledge of the TFD, which represents the transient energy distribution over time and frequency in a joint manner, is very powerful as it allows one to calculate various moments and conditional moments in the time and frequency domains. Based on the experimental time series data collected at Texas A&M University, we calculate the instantaneous frequency center, frequency bandwidth and time duration. The instantaneous power spectrum of the freak wave, where the second harmonic component is observed, allows one to interpret the abnormal wave elevation of the freak wave in time domain. Also, the freak wave is characterized by impulsive joint time-frequency properties, i.e., wider instantaneous frequency bandwidth and shorter time duration than the non-freak waves.

Original languageEnglish
Pages (from-to)32-38
Number of pages7
JournalProceedings of the International Offshore and Polar Engineering Conference
Publication statusPublished - 2004 Dec 1
EventThe Fourteenth International Offshore and Polar Engineering Conference - ISOPE 2004 - Toulon, France
Duration: 2004 May 232004 May 28

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All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Ocean Engineering
  • Mechanical Engineering

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