scholarly journals Holocene coastal evolution, past tsunamis, and extreme wave event reconstructions using sediment cores obtained from the central coast of Hidaka, Hokkaido, Japan

2021 ◽  
pp. 106663
Author(s):  
Ryo Nakanishi ◽  
Juichiro Ashi ◽  
Yosuke Miyairi ◽  
Yusuke Yokoyama
Author(s):  
Richard Gibson ◽  
Chris Swan

Previous work by Baldock, Swan and Taylor [1], Johannessen and Swan [2,3], and Bateman, Swan and Taylor [4,5] has demonstrated that in the vicinity of an extreme wave event there are significant and rapid changes in the local wave spectrum. The present paper combines two recent advances. The first is a new fully nonlinear directional wave model, the application of which is particularly suited to the description of extreme waves arising in realistic sea states. The second involves recent advances in time-frequency analysis techniques. Unlike traditional spectral analysis, based upon the Fourier transform, these allow local and rapid changes in a wave spectrum to be clearly identified. By combining these methods the proposed paper will first highlight the occurrence of these changes in realistic seas and will subsequently demonstrate their significance both in terms of estimating crest height elevations and in predicting the associated water particle kinematics.


2009 ◽  
Vol 29 (1) ◽  
pp. 352-361 ◽  
Author(s):  
Mathijs van Ledden ◽  
Geoffrey Vaughn ◽  
Joost Lansen ◽  
Frank Wiersma ◽  
Mewburn Amsterdam

2007 ◽  
Vol 594 ◽  
pp. 209-247 ◽  
Author(s):  
C. KHARIF ◽  
J.-P. GIOVANANGELI ◽  
J. TOUBOUL ◽  
L. GRARE ◽  
E. PELINOVSKY

The influence of wind on extreme wave events in deep water is investigated experimentally and numerically. A series of experiments conducted in the Large Air–Sea Interactions Facility (LASIF-Marseille, France) shows that wind blowing over a short wave group due to the dispersive focusing of a longer frequency-modulated wavetrain (chirped wave packet) may increase the time duration of the extreme wave event by delaying the defocusing stage. A detailed analysis of the experimental results suggests that extreme wave events may be sustained longer by the air flow separation occurring on the leeward side of the steep crests. Furthermore it is found that the frequency downshifting observed during the formation of the extreme wave event is more important when the wind velocity is larger. These experiments have pointed out that the transfer of momentum and energy is strongly increased during extreme wave events.Two series of numerical simulations have been performed using a pressure distribution over the steep crests given by the Jeffreys sheltering theory. The first series corresponding to the dispersive focusing confirms the experimental results. The second series which corresponds to extreme wave events due to modulational instability, shows that wind sustains steep waves which then evolve into breaking waves. Furthermore, it was shown numerically that during extreme wave events the wind-driven current could play a significant role in their persistence.


Sedimentology ◽  
2020 ◽  
Vol 67 (3) ◽  
pp. 1481-1504 ◽  
Author(s):  
Javier Lario ◽  
Chris Spencer ◽  
Teresa Bardají ◽  
Ángel Marchante ◽  
Victor H. Garduño‐monroy ◽  
...  

2011 ◽  
Vol 5 (2) ◽  
pp. 27-44
Author(s):  
Victor Azevedo Godoi ◽  
Leandro Calado ◽  
Wandrey de Bortoli Watanabe ◽  
Luciana Erika Yaginuma ◽  
Marcos Bastos

2018 ◽  
Vol 45 ◽  
pp. 37-49 ◽  
Author(s):  
Svenja Riedesel ◽  
Dominik Brill ◽  
Helen M. Roberts ◽  
Geoff A.T. Duller ◽  
Ed Garrett ◽  
...  

Author(s):  
Guangyu Wu ◽  
Hyunchul Jang ◽  
Jang Whan Kim ◽  
Wei Ma ◽  
Muo-Chung Wu ◽  
...  

In this study, a numerical wave tank was set up to simulate the free motion of a Tension Leg Platform (TLP) in extreme wave event. For better computational efficiency, a nonlinear potential flow solver is coupled with a CFD software, with the former to simulate the far-field wave domain and the latter to simulate the near-field wave domain and platform motion. In order to benchmark against model test, a five-minute time window of interest was selected from the extreme sea state in model test. The incoming irregular wave was firstly reconstructed from the measured wave time history using the nonlinear potential flow solver and then applied as input to CFD simulations for two different headings to the platform. Static offset tests and free decay tests were simulated in CFD initially to confirm that the platform and tendon properties were properly modeled. The 6-DOF platform motions were then obtained from the CFD simulations and the time histories of motion, air gap, and tendon tension were compared with model test measurements. Good agreements were achieved except for the initial transient period and low-frequency motions. In particular, the air gap or relative wave elevation compared well for all the locations around the platform. The high frequency response in tendon tension and the different tension characteristics of weather side tendons and leeside tendons were also well captured.


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