Showing papers in "Ocean Engineering in 2015"

TL;DR: In this paper, the authors performed a fully nonlinear unsteady RANS simulation to predict the ship motions and added resistance of a full scale KRISO container ship model, and to estimate the increase in effective power and fuel consumption due to its operation in waves.

TL;DR: In this article, a lumped-mass mooring line model was proposed to predict the fair-lead tension and the platform heave response of the DeepCwind semisubmersible floating wind turbine.

TL;DR: A novel computer based algorithm that solves the problem of USV formation path planning using the fast marching (FM) method and has been specifically designed for operation in dynamic environments using the novel constrained FM method.

TL;DR: In this article, an implementation of the dynamic overset grid technique into naoe-FOAM-SJTU solver developed by using the open source code OpenFOAM is presented.

TL;DR: In this paper, a vessel conflict ranking operator (VCRO) is proposed to detect possible near miss ship-ship collisions from AIS data, which considers the following factors affecting the complexity of an encounter between two ships: the distance between the two ships, the relative speed of the ships, and the difference between the headings of ships.

TL;DR: In this paper, the authors proposed an adaptive dynamical sliding mode control based methodology to design control algorithms for the trajectory tracking of underactuated unmanned underwater vehicles (UUVs) in the presence of systematical uncertainty and environmental disturbances.

TL;DR: The main objective of this paper is to present a comprehensive survey of shape and properties of the path and optimization techniques for path planning, which have been classified into different classes and their assumptions and drawbacks have been discussed.

TL;DR: Simulations and image enhancement results show that the proposed method can effectively estimate inherent optical properties of water from the background color of underwater images based on an underwater image formation model and can be used for underwater image enhancement with good performance.

TL;DR: In this paper, a generalized (3+1)-dimensional variable-coefficient B-type Kadomtsev-Petviashvili (KP)-category equations for the nonlinear waves in fluid mechanics, with symbolic computation, were obtained.

TL;DR: In this article, a review of the concept of VLFS, showing how they are deployed for both coastal and offshore areas, is presented, where the MOB project (Mobile Offshore Base) is the design that has been most fully developed.

TL;DR: In this article, a distributed and real-time anti-collision decision support formulation is proposed for collision avoidance in a multi-ship encounter scenario, where the initial decision on collision avoidance by course alteration or speed changing is made according to the encounter situation between own ship and target ships.

TL;DR: It is shown that straightforward statistical distributions can be used to characterize lateral position, speed, heading and interval times for different types and sizes of ships, however, the distributions for different characteristics of ship behaviors differ significantly.

TL;DR: In this paper, a leader-follower formation tracking controller for underactuated autonomous marine surface vehicles with limited torque under environmental disturbances is proposed, where a second-order formation dynamic model is developed in the actuated degrees of freedom of the followers to simplify the design procedure.

TL;DR: In this article, the authors used fuzzy Fault Tree Analysis (FFTA) to analyze the leakage through PA oil and natural gas wells in drilling industry by utilizing Fuzzy Fault Tree analysis.

TL;DR: In this paper, the problem of trajectory tracking control for underactuated unmanned underwater vehicles (UUVs) with model parameter perturbation and constant unknown current in the horizontal plane is addressed, and the globally finite-time tracking control strategy is adopted driving an UUV to track a predefined trajectory.

TL;DR: In this article, the authors investigated the most cost-effective approach to allocate O&M resources which may include helicopter, crew transfer vessels, offshore access vessels, and jack-up vessels.

TL;DR: In this article, an experimental and numerical comparison of the performance of two self-reacting point absorber wave energy converter designs for heave motions is undertaken, and a quantitative comparison is made in terms of displacement, power take-off force requirements, and power capture in typical (non-extreme) operating conditions with reference to theoretical upper bounds.

TL;DR: A comprehensive review of vertical heave motion compensation systems used on ocean vessels from the early 1970s up to, and including, modern systems is provided in this paper, with detailed explanations of the most common motion actuation methods, control schemes, and motion decoupling potential found with each.

TL;DR: In this paper, the effect of scour on the natural frequency of a model monopile was measured in a scale model test and it was shown that wind turbines founded in loose sand would exhibit the largest relative reductions in natural frequency resulting from scour.

TL;DR: A new solver for wave and structure interaction is used for three-dimensional simulation of an Oscillating Water Column and the CFD model solves the Reynolds Averaged Navier–Stokes equations for two incompressible phases.

TL;DR: In this paper, a robust weakly compressible SPH method is applied to simulate violent interactions between free surface and rigid body to calculate forces and torques on rigid body is improved for higher accuracy.

TL;DR: The International Towing Tank Conference specialist committee on Hydrodynamic modelling of Marine Renewable Energy Devices (ITTC) as mentioned in this paper reviewed key issues in the physical and numerical modelling of marine renewable energy systems, including wave energy devices, current turbines, and offshore wind turbines.

TL;DR: In this paper, a modified Kwon method was developed to predict the added resistance caused by wave and wind for a specific ship type, and an easy-to-use semi-empirical ship operational performance prediction model was proposed.

TL;DR: In this article, an approach to evaluate the hydraulic conductivity of soil using cone penetration tests with pore water pressure measurement, known as piezocone testing, was proposed.

TL;DR: In this paper, hydrodynamic characteristics of hydrofoils with leading-edge tubercles were experimentally investigated in a water tunnel at a Reynolds number of Re=1.4×104.

TL;DR: In this paper, a thruster fault tolerant control (FTC) method is developed for underwater vehicles in the presence of modelling uncertainty, external disturbance and unknown thruster faults, which incorporates the sliding mode algorithm and backstepping scheme to improve its robustness to modelling uncertainty and external disturbance.

TL;DR: In this article, a formation controller for desired formation of underactuated autonomous underwater vehicles (AUVs) is proposed under the assumption that the mass and damping matrices are not diagonal and that hydrodynamic damping terms are unknown.

TL;DR: In this paper, a novel "logical virtual ship (LVS) based steering law is developed to program the rational reference route, which is to guidance the underactuated ship in the practical engineering.

TL;DR: In this article, a series of simulations are conducted with various wave conditions, flap configurations and model scales to investigate the viscous and scaling effects on the device, and it is found that the diffraction/radiation effects dominate the device motion and that viscous effects are negligible for wide flaps.

TL;DR: A novel framework for analysing and synthesising engineering system risks on the basis of a generic Fuzzy Evidential Reasoning approach to simplify the inference process and overcome the problems of traditional fuzzy rule based methods in risk analysis and decision making is proposed.