A CFD Application of NewWave Theory to Wave-in-Deck Simulation

2016 ◽  
Vol 13 (02) ◽  
pp. 1640014 ◽  
Author(s):  
Yan Ling Wu ◽  
Graham Stewart ◽  
Yu Chen ◽  
Johan Gullman-Strand ◽  
Xin Lv ◽  
...  
Keyword(s):  
Open Source Software ◽  
Wave Theory ◽  
Numerical Approach ◽  
Air Gap ◽  
Sea Surface ◽  
Extreme Waves ◽  
Extreme Wave ◽  
Large Wave ◽  
The North ◽  
The North Sea

For existing offshore fixed platforms it is often the case that the air gap between the deck and the sea surface is not adequate and the extreme waves will encroach on the deck resulting in large wave-in-deck loads. Factors that result in inadequate air gap are seabed subsidence, sea-level increasing due to climate change and more onerous predictions of extreme crest heights. In this paper, a numerical approach based on NewWave theory [Tromans et al. (1991), Proc. 1st Int. Offshore and Polar Engineering Conf., Vol. 3, Edinburgh, UK, pp. 64–71] has been developed to represent the extreme wave conditions and implemented into the framework of an open source software, OpenFOAM, to predict the wave-in-deck loading. The results have been compared with published FLOW-3D simulations using Stoke’s 5th order wave theory for a simple box representing the Ekofisk platform deck in the Norwegian sector of the North Sea [Iwanowski et al. (2002), Proc. 21st Int. Conf. Offshore Mechanics and Artic Engineering, June 23–28, 2002, Oslo, Norway].

Assessment of Data-Inherited Uncertainty in Extreme Wave Analysis

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Ryota Wada ◽  
Takuji Waseda
Keyword(s):  
Gulf Of Mexico ◽  
North Sea ◽  
Epistemic Uncertainty ◽  
Accurate Estimation ◽  
Extreme Waves ◽  
Wave Analysis ◽  
Extreme Wave ◽  
The North ◽  
Sample Data ◽  
The North Sea

Abstract Accurate estimation of extreme wave condition is desired for the rational design of offshore structures, but the estimation results are known to have uncertainty from various sources. The quality and quantity of the available extreme wave data differ among ocean regions since the atmospheric causes of extreme waves are not identical. This paper provides insight into how the different extreme wave behaviors influence the uncertainty of extreme wave estimation at each location. A review of extreme waves in four regions, namely the Gulf of Mexico, North West Pacific, Adriatic Sea, and the North Sea, revealed the difference in data uncertainty, shape parameter, and frequency of occurrence. The likelihood-weighted method was introduced to quantitatively assess the impact of each parameter on the uncertainty of extreme wave analysis. Case study based on representative parameters of the Gulf of Mexico and the North Sea revealed the large epistemic uncertainty for a region dominated by tropical cyclones. The assessment conducted in this paper is unique as it evaluates the epistemic uncertainty inherited in the extreme sample data. When the epistemic uncertainty is large, such as the case illustrated for the Gulf of Mexico, the variance from different approaches may not be significant against the epistemic uncertainty inherited in the sample data.

scholarly journals Influence of Sea State on Sea Surface Height Oscillation from Doppler Altimeter Measurements in the North Sea

2018 ◽  
Vol 10 (7) ◽  
pp. 1100 ◽  
Author(s):  
Ferdinando Reale ◽  
Fabio Dentale ◽  
Eugenio Carratelli ◽  
Luciana Fenoglio-Marc
Keyword(s):  
North Sea ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Sea State ◽  
The North ◽  
The North Sea

scholarly journals North Atlantic storm driving of extreme wave heights in the North Sea

2017 ◽  
Vol 122 (4) ◽  
pp. 3253-3268 ◽  
Author(s):  
R. J. Bell ◽  
S. L. Gray ◽  
O. P. Jones
Keyword(s):  
North Sea ◽  
North Atlantic ◽  
Extreme Wave ◽  
The North ◽  
Wave Heights ◽  
The North Sea

PAST AND FUTURE CHANGES IN THE NORTH SEA EXTREME WAVES

2009 ◽  
Author(s):  
Sofia Caires ◽  
Jacco Groeneweg ◽  
Andreas Sterl
Keyword(s):  
North Sea ◽  
Extreme Waves ◽  
The North ◽  
The North Sea

Imaging the sea surface using a dual-sensor towed streamer

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. V111-V118 ◽  
Author(s):  
Okwudili Orji ◽  
Walter Söllner ◽  
Leiv Jacob Gelius
Keyword(s):  
Seismic Data ◽  
Time Window ◽  
Finite Difference Methods ◽  
Surface Profile ◽  
Sea Surface ◽  
Data Sets ◽  
The North ◽  
Dual Sensor ◽  
The North Sea ◽  
Time Invariant

Sea-surface profile and reflection coefficient estimates are vital input parameters to various seismic data processing applications. The common assumption of a flat sea surface when processing seismic data can lead to misinterpretations and mislocations of events. A new method of imaging the sea surface from decomposed wavefields has been developed. Wavefield separation is applied to the data acquired by a towed dual-sensor streamer containing collocated pressure and vertical particle velocity sensors to obtain upgoing and downgoing wavefields of the related sensors. Time-gated upgoing and downgoing wavefields corresponding to a given sensor are then extrapolated to the sea surface where an imaging condition is applied so that the time-invariant shape of the sea surface can be recovered. By sliding the data time-window, the temporal changes of the sea surface can be correspondingly estimated. Ray tracing and finite-difference methods were used to generate different controlled data sets used in this feasibility study to demonstrate the imaging principle and to test the image accuracy. The method was also tested on a first field data example of a marginal weather line from the North Sea.

Long-term trends in the distribution, abundance and seasonal occurrence of larvae of mackerel (Scomber scombrus L.) around the British Isles, 1948–1978

1981 ◽  
Vol 61 (2) ◽  
pp. 343-358 ◽  
Author(s):  
S. H. Coombs ◽  
C. E. Mitchell
Keyword(s):  
Surface Temperature ◽  
North Sea ◽  
Sea Surface ◽  
Seasonal Occurrence ◽  
British Isles ◽  
Scomber Scombrus ◽  
The North ◽  
The North Sea ◽  
Long Term Trends

The distribution, abundance and seasonal occurrence of larvae of mackerel (Scomber scombrus L.) are described from routine Continuous Plankton Recorder (CPR) sampling around the British Isles over the period 1948–78, and from more intensive CPR sampling in the Celtic Sea in 1977. There were two main areas of larval concentration: in the North Sea and over and adjacent to the Celtic Plateau; subsidiary aggregations were observed to the northwest of Ireland and to the west of Norway. There were some similarities between the distribution of larvae around the British Isles and that of adult Calanus spp. In the North Sea there was a southerly shift of larval distribution over the period 1948–77; over a similar period the abundance of larvae increased to reach high numbers by the late 1950s and subsequently declined after the mid-6os. To the south-west of the British Isles numbers of larvae showed a long-term decline. The long-term trends of distribution and abundance are discussed in relation to concurrent biological and environmental change. The clearest relationship was found between the numbers of mackerel larvae in the North Sea and sea-surface temperature in the North Atlantic, which suggests a common causative agent for both sets of observations; also, there was a weak relationship with both spawning stock biomass and sea-surface temperature at the spawning areas. In the North Sea the seasonal occurrence of larvae was from May to August, the majority being taken in June and July; over the period 1948–77 the seasonal time of occurrence of highest numbers of larvae has remained relatively constant. In the Celtic Sea the seasonal occurrence of larvae was spread over a longer period, from March to August, with relatively high numbers from March to June; over the period 1950–78 the time of occurrence has been variable, possibly with a tendency towards later timing in more recent years.

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