Nonlinear Evolution of Directional Wave Spectra in Shallow Water

1995 ◽  
Author(s):  
Okey Nwogu
Keyword(s):  
Shallow Water ◽  
Nonlinear Evolution ◽  
Wave Spectra ◽  
Directional Wave

Directional Wave Spectra from Video Images Data and SWAN Model

2015 ◽  
Vol 74 (5) ◽  
Author(s):  
Muhammad Zikra ◽  
Noriaki Hashimoto ◽  
Masaru Yamashiro ◽  
Kojiro Suzuki
Keyword(s):  
Shallow Water ◽  
Water Area ◽  
Paper Analysis ◽  
Wave Spectra ◽  
Swan Model ◽  
Video Images ◽  
Shallow Water Area ◽  
Directional Wave ◽  
Probe Sensor ◽  
Rectification Process

In this paper, analysis of directional wave spectra in shallow water area estimated by video images data has been compared with numerical model of SWAN. Estimation of directional wave spectra from video images is based on the Bayesian Directional Method using a group of pixels brightness on the image. For this study, the pixels can be considered equivalent to fixed instruments as wave probe sensor after rectification process. The results show that there is a good agreement between directional wave spectra estimated by video images data and the SWAN model. Both methods estimate similar shape of directional wave spectra in the shallow water. In addition, the energy distribution of directional wave spectra in shallow water is concentrated significantly in frequency and direction. 

scholarly journals APPLICATION OF VIDEO IMAGES FOR MONITORING COASTAL ZONE IN HASAKI BEACH, JAPAN

2012 ◽  
Vol 1 (33) ◽  
pp. 43
Author(s):  
Muhammad Zikra ◽  
Noriaki Hashimoto ◽  
Masaru Yamashiro ◽  
Masaki Yokota ◽  
Kojiro Suzuki
Keyword(s):  
Shallow Water ◽  
Coastal Zone ◽  
Image Data ◽  
Field Measurements ◽  
Video Camera ◽  
Video Image ◽  
Wave Spectra ◽  
Digital Video Camera ◽  
Directional Wave ◽  
Pixel Brightness

The video image analysis methods are used for monitoring the phenomena at the coastal zone. A digital video camera which is mounted in the HORS research building is used to estimate directional wave spectra and bathymetry in shallow water areas. The Bayesian Directional Method is used to estimate directional wave spectra using the group of pixels brightness and non-linear bathymetry inversion is used to estimate shallow water bathymetry using time series of pixel brightness intensity at cross-shore and longshore array. The results are compared with a numerical model and field measurements. The results indicate that video image data could be used to estimate bathymetry and directional wave spectra in shallow water areas.

scholarly journals Ship Motions in Shallow Water As the Base for a Probabilistic Approach Policy

2008 ◽  
Author(s):  
Marc Vantorre ◽  
Erik Laforce ◽  
Katrien Eloot ◽  
Jan Richter ◽  
Jeroen Verwilligen ◽  
...  
Keyword(s):  
Shallow Water ◽  
Probabilistic Approach ◽  
Ship Motions ◽  
Wave Spectra ◽  
Fluid Mud ◽  
Response Functions ◽  
Regular Waves ◽  
Directional Wave ◽  
Probabilistic Criteria ◽  
Selection Of

A calculation tool has been developed for determining tidal windows for deep-drafted ships approaching and leaving the Belgian harbors according to probabilistic criteria. The calculations are based on a database containing response functions for the vertical motions in waves and squat data for a selection of representative ships. The database contains both results of model tests carried out in the Towing tank for maneuvers in shallow water – co-operation Flanders Hydraulics Research & Ghent University in Antwerp (Belgium), as well as calculated values. During the experiments, draft, trim, under keel clearance (7 to 20% of draft) and speed have been varied. The tests were performed in regular waves with lengths which are small compared to ship length, and in wave spectra that are typical for the Belgian coastal area. For given input data (ship characteristics, speed, tide, directional wave spectra, bottom, trajectory, current, departure time), the tool calculates the probability of bottom touch during the transit, so that a tidal window can be determined. Other restrictions, such as penetration into fluid mud layers and current, are taken into account as well.

Analysis of Directional Wave Spectra in Shallow Water Areas Using Video Image Data

2012 ◽  
Vol 54 (3) ◽  
pp. 1250020-1-1250020-24 ◽  
Author(s):  
Muhammad Zikra ◽  
Noriaki Hashimoto ◽  
Masaru Yamashiro ◽  
Masaki Yokota ◽  
Kojiro Suzuki
Keyword(s):  
Shallow Water ◽  
Image Data ◽  
Video Image ◽  
Wave Spectra ◽  
Directional Wave

Multi-peaked directional wave spectra based on extensive field measurement data in the Gulf of Oman

2021 ◽  
Vol 230 ◽  
pp. 109057
Author(s):  
Mohammad Adibzade ◽  
Mehdi Shafieefar ◽  
Hassan Akbari ◽  
Roozbeh Panahi
Keyword(s):  
Field Measurement ◽  
Measurement Data ◽  
Wave Spectra ◽  
Gulf Of Oman ◽  
Extensive Field ◽  
Directional Wave
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