Selecting the Best Heading for FPSOs in Santos Basin Considering the Wave Induced Motions

2012 ◽  
Author(s):  
Mauro Costa de Oliveira
Keyword(s):  
Search Algorithm ◽  
Wave Climate ◽  
Design Decision ◽  
Operational Conditions ◽  
Field Development ◽  
Induced Motion ◽  
Wave Induced ◽  
Motion Behavior ◽  
Statistical Results ◽  
Selection Of

The selection of the best heading considering the wave induced motion behavior is a design decision that should be taken in the early stages of the field development. Particularly for FPSOs with spread mooring pattern, that are not weathervane, this can bring the reduction of angular motions and accelerations, leading to better operational conditions, reduced wave induced loading acting on the FPSO deck structures and over the risers. The procedure adopted to select an optimized heading, is based in the analysis of several cases covering all the wave environment of Santos Basin, Offshore Brazil, and assessing parameters like roll motion and riser connection accelerations in order to select the optimum heading range. This problem has several input sea states, once the wave climate is defined by the extreme contour curves for the 100 year data. Another aspect is related to the combination of the FPSO loading conditions, which add more variables to the problem. A search algorithm have been implemented to enable the comparison of a large number of statistical results and to determine an adequate heading for the FPSOs.

An Iceberg Collision Reliability Model Incorporating Hydrodynamic Effects

1990 ◽  
Vol 112 (4) ◽  
pp. 364-369
Author(s):  
M. Isaacson ◽  
K. A. McTaggart
Keyword(s):  
Kinetic Energy ◽  
Energy Levels ◽  
Added Mass ◽  
Wave Climate ◽  
Climate Data ◽  
Offshore Structure ◽  
Reliability Method ◽  
Wave Induced ◽  
Hydrodynamic Effects ◽  
Selection Of

A probabilistic model is developed for the selection of a design iceberg collision event with a fixed offshore structure. The model has been formulated such that input parameters can be obtained from available iceberg surveillance and wave climate data. Once input data for a given site are obtained, probabilities of exceedance for various kinetic energy levels are estimated using a second-order reliability method. A key feature of the model is its incorporation of wave-induced motions and added mass in the evaluate of iceberg kinetic energy.

scholarly journals Optimal Selection of Conductors in Three-Phase Distribution Networks Using a Discrete Version of the Vortex Search Algorithm

Computation ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 80
Author(s):  
John Fernando Martínez-Gil ◽  
Nicolas Alejandro Moyano-García ◽  
Oscar Danilo Montoya ◽  
Jorge Alexander Alarcon-Villamil
Keyword(s):  
Objective Function ◽  
Power Flow ◽  
Phase Distribution ◽  
Search Algorithm ◽  
Distribution Networks ◽  
Discrete Version ◽  
Optimal Selection ◽  
Flow Method ◽  
Three Phase ◽  
Selection Of

In this study, a new methodology is proposed to perform optimal selection of conductors in three-phase distribution networks through a discrete version of the metaheuristic method of vortex search. To represent the problem, a single-objective mathematical model with a mixed-integer nonlinear programming (MINLP) structure is used. As an objective function, minimization of the investment costs in conductors together with the technical losses of the network for a study period of one year is considered. Additionally, the model will be implemented in balanced and unbalanced test systems and with variations in the connection of their loads, i.e., Δ− and Y−connections. To evaluate the costs of the energy losses, a classical backward/forward three-phase power-flow method is implemented. Two test systems used in the specialized literature were employed, which comprise 8 and 27 nodes with radial structures in medium voltage levels. All computational implementations were developed in the MATLAB programming environment, and all results were evaluated in DigSILENT software to verify the effectiveness and the proposed three-phase unbalanced power-flow method. Comparative analyses with classical and Chu & Beasley genetic algorithms, tabu search algorithm, and exact MINLP approaches demonstrate the efficiency of the proposed optimization approach regarding the final value of the objective function.

scholarly journals Memory Based Cuckoo Search Algorithm for Feature Selection of Gene Expression Dataset

2021 ◽  
pp. 100572
Author(s):  
Malek Alzaqebah ◽  
Khaoula Briki ◽  
Nashat Alrefai ◽  
Sami Brini ◽  
Sana Jawarneh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Feature Selection ◽  
Search Algorithm ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Gene Expression Dataset ◽  
Selection Of

Assessing Product Lifecycle Sustainability Using Uncertain Design Information at Conceptual Stage

2008 ◽  
Author(s):  
Q. Z. Yang ◽  
B. Song
Keyword(s):  
Conceptual Design ◽  
Product Information ◽  
Sustainability Assessment ◽  
Early Stage ◽  
Evaluation Model ◽  
Evaluation Criteria ◽  
Design Decision ◽  
Fuzzy Evaluation ◽  
Product Lifecycle ◽  
Selection Of

This paper presents a hierarchical fuzzy evaluation approach to product lifecycle sustainability assessment at conceptual design stages. The purpose is to advocate the emerging use of lifecycle engineering methods in support of evaluation and selection of design alternatives for sustainable product development. A fuzzy evaluation model is developed with a hierarchical criteria structure to represent different sustainability considerations in the technical, economic and environmental dimensions. Using the imprecise and uncertain early-stage product information, each design option is assessed by the model with respect to the hierarchical evaluation criteria. Lifecycle engineering methods, such as lifecycle assessment and lifecycle costing analysis, are applied to the generation of the evaluation criteria. This would provide designers with a more complete lifecycle view about the product’s sustainability potentials to support decision-making in evaluation and selection of conceptual designs. The proposed approach has been implemented in a sustainable design decision-support software prototype. Illustrative examples are discussed in the paper to demonstrate the use of the approach and the prototype in conceptual design selection of a consumer product.

Wave induced turbulence effect on oceanic biogeochemistry and study of ocean color response to changing wave climate

2021 ◽  
Author(s):  
Chinglen Meetei Tensubam ◽  
Alexander V. Babanin
Keyword(s):  
Net Primary Productivity ◽  
Mixed Layer Depth ◽  
Marine Ecosystem ◽  
Ocean Color ◽  
Ocean Waves ◽  
Wave Climate ◽  
Upper Ocean ◽  
P Value ◽  
Chl A ◽  
Wave Induced

<p>The role of surface ocean waves becomes substantial in the upper ocean layer mixing. Due to turbulence induced by the surface waves (both broken and unbroken waves), the upper ocean mixing is enhanced, and important upper ocean parameters are affected such as lowering of sea surface temperature (SST), deepening of mixed layer depth (MLD) and most interestingly, the changes in oceanic biogeochemistry. The main objective of this study is to analyze the effect of wave induced turbulence on oceanic biogeochemistry such as the supply and distribution of nutrients to tiny plants in the ocean called phytoplanktons, and how it affects their concentrations. Marine phytoplanktons formed the basis of marine ecosystem which accounts for about 45 percent of global net primary productivity and play an important part in global carbon cycle. The population of phytoplanktons depends mainly on nutrients (both micro and macro), availability of sunlight and grazing organisms. For this study, we use global coupled ocean-sea ice model ACCESS-OM2 with biogeochemical module called WOMBAT to estimate the effect of wave induced turbulence and study the difference between ‘with waves’ and ‘without waves’ effect on oceanic biogeochemistry. The same effect of wave induced turbulence on oceanic biogeochemistry are also studied by incorporating the change in wave climate such as increase in significant wave height and wind speed. From the investigation of merged satellite ocean color data from ESA’s GlobColour project for the period of 23 years between 1997 and 2019, it was found that chlorophyll-a (Chl-a, an index of phytoplankton biomass) concentration showed increasing trend of 0.015 mg/m3 globally and 0.062 mg/m3 in the Southern Ocean (SO) for the study period with p-value less than 0.01. It was also found that most of the increasing trends are shown spatially in the open ocean and decreasing trend in the coastal regions during the study period.</p>

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