Review of Hydrodynamic and Nautical Studies for Offshore LNG Operations

2013 ◽  
Author(s):  
Jaap de Wilde ◽  
Johan Dekker
Keyword(s):  
Time Domain ◽  
Model Tests ◽  
Fast Time ◽  
Maneuvering Simulations ◽  
Critical Aspects

In this paper we review hydrodynamic and nautical studies for offshore LNG operations. Based on full mission bridge simulations, model tests campaigns, time domain simulations, fast time maneuvering simulations and downtime assessments, we address the major findings in terms of weather limitations, tugboat requirements and other critical aspects for the berthing and offloading operation.

Detection of Mooring Line Failure of a Spread-Moored FPSO: Part 2 — Global Performance Analysis Using MLTSIM

2019 ◽  
Author(s):  
Johyun Kyoung ◽  
Ho-Joon Lim ◽  
Djoni E. Sidarta ◽  
Nicolas Tcherniguin ◽  
Timothee Lefebvre
Keyword(s):  
Performance Analysis ◽  
Numerical Simulations ◽  
Motion Analysis ◽  
Time Domain ◽  
Model Tests ◽  
Mooring Line ◽  
Fast Time ◽  
Ann Model ◽  
Wide Range ◽  
Global Performance

Abstract This paper presents Part 2 in the development of an Artificial Neural Network (ANN) model for detection of mooring line failure of a spread-moored FPSO, global performance analysis used to generate the training and test data for the study. The development of an ANN model for detection of mooring line failure requires a comprehensive training data that is most practically available from the results of numerical simulations. Time domain analysis is necessary to capture the nonlinear behavior of a moored FPSO system and to represent the behavior of the physical system as accurate as possible. Given the wide range of sea-state conditions, of direction of the sea-states and of draft conditions of the FPSO, the number of time domain simulations is easily larger than 100,000. Therefore, an accurate and numerically efficient tool is necessary for carrying this task. The FPSO hull motion analysis is performed using MLTSIM, a TechnipFMC in-house, nonlinear time domain floating body motion analysis program. MLTSIM captures various non-linear load and response effects such as mooring stiffness, riser loads, drag and drift forces, as well as various user defined loads. MLTSIM is a numerically efficient and fast time domain solver which can run on both high-performance computing (HPC) system and a single laptop. Numerical model of a FPSO system has been validated using the results of model tests. In addition, the results of numerical simulations, in terms of hull motions and mooring line tensions, are compared with the results of model tests and a commercial software OrcaFlex. This well-calibrated model is then used for generating the numerical data required for the development of the ANN model.

Fast Time Domain Integral Equation Solvers for Large-Scale Electromagnetic Analysis

2004 ◽  
Author(s):  
Eric Michielsssen ◽  
Weng C. Chew ◽  
Jianming Jin ◽  
Balasubramaniam Shanker
Keyword(s):  
Integral Equation ◽  
Time Domain ◽  
Large Scale ◽  
Electromagnetic Analysis ◽  
Fast Time ◽  
Domain Integral ◽  
Time Domain Integral Equation

Fast time domain reflectometry (TDR) measurement approach for investigating the liquefaction of soils

2010 ◽  
Vol 21 (2) ◽  
pp. 025104 ◽  
Author(s):  
A Scheuermann ◽  
C Hübner ◽  
H Wienbroer ◽  
D Rebstock ◽  
G Huber
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Fast Time ◽  
Measurement Approach

scholarly journals Fast Time-Domain Simulation for Reliable Fault Detection

2016 ◽  
Author(s):  
Bratislav Tasić ◽  
Jos J. Dohmen ◽  
Rick Janssen ◽  
E. Jan W. ter Maten ◽  
Roland Pulch ◽  
...  
Keyword(s):  
Fault Detection ◽  
Time Domain ◽  
Fast Time ◽  
Time Domain Simulation

Clustering Applied to Large Sets of Environmental Conditions for Selecting Typical Scenarios for Ship Maneuvering Real-Time Simulations

2021 ◽  
Author(s):  
Felipe M. Moreno ◽  
Eduardo A. Tannuri
Keyword(s):  
Time Series ◽  
Cluster Analysis ◽  
Environmental Conditions ◽  
Wind Waves ◽  
Fast Time ◽  
Large Set ◽  
Ship Maneuvering ◽  
Partitioning Around Medoids ◽  
Waves And Currents ◽  
Maneuvering Simulations

Abstract The methodology described in this paper is used to reduce a large set of combined wind, waves, and currents to a smaller set that still represents well enough the desired site for ship maneuvering simulations. This is achieved by running fast-time simulations for the entire set of environmental conditions and recording the vessel’s drifting time-series while it is controlled by an automatic-pilot based on a line-of-sight algorithm. The cases are then grouped considering how similar the vessel’s drifting time-series are, and one environmental condition is selected to represent each group found by the cluster analysis. The measurement of dissimilarity between the time-series is made by application of Dynamic Time Warping and the Cluster Analysis is made by the combination of Partitioning Around Medoids algorithm and the Silhouette Method. Validation is made by maneuvering simulations made with a Second Deck Officer.

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