Who Rules the Waves? -- A Case Study in System Description

1983 ◽  
Vol 34 (9) ◽  
pp. 885-898 ◽  
Author(s):  
R. G. Coyle
Keyword(s):  
System Description ◽  
The Waves

Evaluating the Coupledness of the Aerodynamics and Hydrodynamics on the Estimation of Fatigue Damage Equivalent Load for a Floating Offshore Wind Platform

2018 ◽  
Author(s):  
Samuel Kanner ◽  
Bingbin Yu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Environmental Conditions ◽  
Offshore Wind ◽  
Coupled Analysis ◽  
Offshore Wind Turbine ◽  
Wave Conditions ◽  
Equivalent Load ◽  
The Waves

In this research, the estimation of the fatigue life of a semi-submersible floating offshore wind platform is considered. In order to accurately estimate the fatigue life of a platform, coupled aerodynamic-hydrodynamic simulations are performed to obtain dynamic stress values. The simulations are performed at a multitude of representative environmental states, or “bins,” which can mimic the conditions the structure may endure at a given site, per ABS Floating Offshore Wind Turbine Installation guidelines. To accurately represent the variety of wind and wave conditions, the number of environmental states can be of the order of 103. Unlike other offshore structures, both the wind and wave conditions must be accounted for, which are generally considered independent parameters, drastically increasing the number of states. The stress timeseries from these simulations can be used to estimate the damage at a particular location on the structure by using commonly accepted methods, such as the rainflow counting algorithm. The damage due to either the winds or the waves can be estimated by using a frequency decomposition of the stress timeseries. In this paper, a similar decoupled approach is used to attempt to recover the damages induced from these coupled simulations. Although it is well-known that a coupled, aero-hydro analysis is necessary in order to accurately simulate the nonlinear rigid-body motions of the platform, it is less clear if the same statement could be made about the fatigue properties of the platform. In one approach, the fatigue damage equivalent load is calculated independently from both scatter diagrams of the waves and a rose diagram of the wind. De-coupled simulations are performed to estimate the response at an all-encompassing range of environmental conditions. A database of responses based on these environmental conditions is constructed. The likelihood of occurrence at a case-study site is used to compare the damage equivalent from the coupled simulations. The OC5 platform in the Borssele wind farm zone is used as a case-study and the damage equivalent load from the de-coupled methods are compared to those from the coupled analysis in order to assess these methodologies.

Extreme waves and surges interaction with tides during storms in winter 2013/2014.

2021 ◽  
Author(s):  
Julia Rulent
Keyword(s):  
Tidal Cycle ◽  
Grid Point ◽  
High Tide ◽  
Water Levels ◽  
Extreme Waves ◽  
Near Shore ◽  
The Uk ◽  
The Waves ◽  
Tidal Stage

<p>The interaction between waves, surges and tides is one of the main drivers of coastal total water levels (TWL).  Understanding this interaction is crucial for studying high TWL formation near shore, and to do this it is important to not only evaluate how high the TWL is but also when and where it occurs.</p><p>In this study we use a high resolution (1.5 km) three-way coupled (waves-atmosphere-ocean) numerical model developed by the MetOffice (UKC4) to study coastal conditions at the UK coast during the extreme events of winter 2013, which was chosen as case study because of the amount of flooding that occurred in relation to storms and surges during this period.</p><p>For each coastal grid point the ten strongest storms of that winter, ranked by the significant wave height (Hs) magnitude, were selected. During these storm periods, the number of hours in which Hs and surges exceeded the 90<sup>th</sup> percentile of winter 2013 were evaluated considering what tidal stage they occurred on. The same was done for instances where high Hs and surges occurred simultaneously. The aim is to understand if specific areas were predominantly affected by one of the TWL components and how Hs and surges interacted with the tide. What was the spatial distribution of the waves, surges, and tides during winter 2013? Did extreme Hs and Surges occur more often over specific stages of the tidal cycle? Did they occur simultaneously? </p><p>In this study we show that during the winter 2013, Hs and surges above the 90<sup>th</sup> percentile value did occur simultaneously at all stages of the tidal cycle. They more often occurred together over the rising tide with in average 8.7% and 8.6% of instances found two and three hours before high tide. In 7.7% of cases high wave and surges also concurred at high tide.</p>

scholarly journals Role of tropical mid-latitude interaction in the genesis of a monsoon depression - A detailed case study

MAUSAM ◽  
2021 ◽  
Vol 49 (2) ◽  
pp. 159-166
Author(s):  
KSHUDIRAM SARA ◽  
SURANJANA SARA
Keyword(s):  
South China ◽  
Wave Interaction ◽  
Stationary Wave ◽  
Monsoon Depression ◽  
Wind Fields ◽  
Northern Summer ◽  
Profound Influence ◽  
The Waves

During northern summer, a monsoon stationary wave which maintains as part of its baroclinic structure three well-defined troughs, one each in the region of the Arabian sea, the Bay of Bengal and South China sea, frequently interacts with the mid-latitude baroclinic waves which amplify during their eastward passage with profound influence on the development of the monsoon troughs. The paper discusses the mechanism of this wave-wave interaction as suggested by the temporal evolution of the themla1 and wind fields associated with the waves and reports the findings of a detailed study of a case of tropical-mid latitude interaction in which the development of a monsoon trough led to the birth of a westward-propagating monsoon depression over South China.

Market structure and horizontal growth strategies – A case study of the container shipping industry

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Nguyen Khoi Tran
Keyword(s):  
Strategic Alliances ◽  
Container Shipping ◽  
Shipping Industry ◽  
Growth Strategies ◽  
Market Shares ◽  
Horizontal Growth ◽  
Service Coverage ◽  
The Waves ◽  
External Growth

Abstract This article aims to review the structural transformation in the container shipping industry from 1995 to 2020 and identify the growth strategies of global carriers to enhance their market presence. Along with large investments in mega vessels, the growing deployment of charter capacity in all ship sectors has been a prominent trend in fleet expansion. The waves of mergers/acquisitions and bankruptcies have narrowed the group of global carriers. In addition to internal and external growth, they have been increasingly involved in strategic alliances to expand service coverage and compete well with powerful rivals. A few mega carriers have progressively captured the industry. In 2020, the Top 12 controlled 88 % of the global supply, and nearly 56 % was in the hands of the Top 4. Besides the substantial expansion of the four biggest carriers, we can identify the de-concentration within this gigantic group through the less inequality between their market shares.

scholarly journals Study of a hydraulic system converting energy from sea waves near the coast

2018 ◽  
Vol 240 ◽  
pp. 01004 ◽  
Author(s):  
Silvio Barbarelli ◽  
Mario Amelio ◽  
Gaetano Florio ◽  
Nino Michele Scornaienchi
Keyword(s):  
Hydraulic System ◽  
Constant Pressure ◽  
Piston Pump ◽  
Energy Output ◽  
Sea Waves ◽  
Floating Structure ◽  
Pelton Turbine ◽  
Reference Parameters ◽  
The Waves

This paper proposes a system able to recover energy from sea waves. The system is made up essentially of a floating structure, connected to a piston pump. The pump, constrained to move vertically under the action of the waves, pushes water into a reservoir maintained at constant pressure, from which it flows in a Pelton turbine. A methodology was developed for the preliminary sizing of the proposed system. This methodology takes the height of the waves and the pressure of the reservoir as reference parameters and then provides the main geometric data of the machines. A case study developed in the present work, demonstrates the possibility of designing miniaturized components of the system, able anyway to provide acceptable energy output with contained installation costs.

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