Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas
An understanding of the wave height distribution of a sea state is important in forecasting extreme wave height and lifetime fatigue predictions of marine structures. In bimodal seas, swell can be present at different percentages and different frequencies while the energy content of the sea state re...
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doaj-1100c86c4c8646ebb47911bffdde6b282021-04-02T15:19:32ZengMDPI AGJournal of Marine Science and Engineering2077-13122019-03-01737910.3390/jmse7030079jmse7030079Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal SeasStephen Orimoloye0Harshinie Karunarathna1Dominic E. Reeve2Department of Civil Engineering, Energy & Environment Research Group, Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea SA1 8EN, UKDepartment of Civil Engineering, Energy & Environment Research Group, Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea SA1 8EN, UKDepartment of Civil Engineering, Energy & Environment Research Group, Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea SA1 8EN, UKAn understanding of the wave height distribution of a sea state is important in forecasting extreme wave height and lifetime fatigue predictions of marine structures. In bimodal seas, swell can be present at different percentages and different frequencies while the energy content of the sea state remains unaltered. This computational study investigates how the wave height distribution is affected by different swell percentages and long swell periods in an energy-conserved bimodal sea both near a wave maker and in shallow water. A formulated energy-conserved bimodal spectrum was created from unimodal sea states and converted into random waves time series using the Inverse Fast Fourier Transform (IFFT). The resulting time series was used to drive a Reynolds-Averaged Navier Stokes computational (RANS) model. Wave height values were then extracted from the model results (both away near and near the structure) using down-crossing analysis to inspect the non-linearity imposed by wave-wave interactions and through transformations as they propagate into shallow waters near the structure. It is concluded that the kurtosis and skewness of the wave height distribution very inversely with the swell percentage and peak periods. Non-linearities are greater in the unimodal seas compared to the bimodal seas with the same energy content. Also, non-linearities are greater structure side than at wave maker and are more dependent on the phases of the component waves at different frequencies.https://www.mdpi.com/2077-1312/7/3/79energy distributionbimodal seasswell percentagesIH2VOFwave steepnessnon-linearities |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Stephen Orimoloye Harshinie Karunarathna Dominic E. Reeve |
spellingShingle |
Stephen Orimoloye Harshinie Karunarathna Dominic E. Reeve Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas Journal of Marine Science and Engineering energy distribution bimodal seas swell percentages IH2VOF wave steepness non-linearities |
author_facet |
Stephen Orimoloye Harshinie Karunarathna Dominic E. Reeve |
author_sort |
Stephen Orimoloye |
title |
Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas |
title_short |
Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas |
title_full |
Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas |
title_fullStr |
Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas |
title_full_unstemmed |
Effects of Swell on Wave Height Distribution of Energy-Conserved Bimodal Seas |
title_sort |
effects of swell on wave height distribution of energy-conserved bimodal seas |
publisher |
MDPI AG |
series |
Journal of Marine Science and Engineering |
issn |
2077-1312 |
publishDate |
2019-03-01 |
description |
An understanding of the wave height distribution of a sea state is important in forecasting extreme wave height and lifetime fatigue predictions of marine structures. In bimodal seas, swell can be present at different percentages and different frequencies while the energy content of the sea state remains unaltered. This computational study investigates how the wave height distribution is affected by different swell percentages and long swell periods in an energy-conserved bimodal sea both near a wave maker and in shallow water. A formulated energy-conserved bimodal spectrum was created from unimodal sea states and converted into random waves time series using the Inverse Fast Fourier Transform (IFFT). The resulting time series was used to drive a Reynolds-Averaged Navier Stokes computational (RANS) model. Wave height values were then extracted from the model results (both away near and near the structure) using down-crossing analysis to inspect the non-linearity imposed by wave-wave interactions and through transformations as they propagate into shallow waters near the structure. It is concluded that the kurtosis and skewness of the wave height distribution very inversely with the swell percentage and peak periods. Non-linearities are greater in the unimodal seas compared to the bimodal seas with the same energy content. Also, non-linearities are greater structure side than at wave maker and are more dependent on the phases of the component waves at different frequencies. |
topic |
energy distribution bimodal seas swell percentages IH2VOF wave steepness non-linearities |
url |
https://www.mdpi.com/2077-1312/7/3/79 |
work_keys_str_mv |
AT stephenorimoloye effectsofswellonwaveheightdistributionofenergyconservedbimodalseas AT harshiniekarunarathna effectsofswellonwaveheightdistributionofenergyconservedbimodalseas AT dominicereeve effectsofswellonwaveheightdistributionofenergyconservedbimodalseas |
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1721560184497635328 |