Showing papers in "Ocean Engineering in 2012"

TL;DR: The vision-based object detection and tracking techniques for underwater robots have been studied in depth and a number of approaches have been tested, including color restoration algorithm for the degraded underwater images, detection andtracking methods for underwater target objects.

TL;DR: In this article, an advanced model for predicting a two-dimensional coupled cross-flow/in-line VIV of a flexibly mounted circular cylinder in a uniform flow is proposed and validated.

TL;DR: A parametric study on arrays of wave energy converters (WECs) is presented in this article, where the authors assess the influence of interactions between bodies on the overall yearly energy production of the array.

TL;DR: In this paper, a two-dimensional SPH-FEM model is proposed to investigate its application in the fluid-structure interaction (FSI) problem, where the fluid model is based on the theory of Smoothed Particle Hydrodynamics (SPH) and the structural dynamics employ a large deformation Finite Element Method (FEM).

TL;DR: Aiming at the chattering problem which is caused by sliding mode control item, a switch gain adjust method based on exponential function is proposed, which proves that the trajectory tracking error of the underwater robot control system is uniformly ultimately bounded through Lyapunov theory.

TL;DR: In this article, the effect of the vertical baffle height on the liquid sloshing in a laterally moving three-dimensional (3D) rectangular tank was investigated, where the volume of fluid (VOF) method based on the finite volume method was utilized.

TL;DR: In this paper, the numerical simulation of both linear deep water waves and linear waves for the finite depth case are explored using computational fluid dynamics (CFD), to aid in the design of wave energy converters.

TL;DR: In this paper, a methodology for estimating the attainable ship speed in moderate and severe sea is proposed, where the irregular sea is handled as a series of regular waves with different amplitudes and frequencies.

TL;DR: In this paper, the authors presented the results of three-dimensional finite element analyses of bucket foundations in normally consolidated uniform clay under undrained conditions, and the bearing capacities were calculated and found to be largely dependent on the aspect ratio of the bucket foundation.

TL;DR: In this paper, an extended Kalman filter (EKF) based adaptive control method for an autonomous underwater vehicle-manipulator system (UVMS) based on an EKF was proposed.

TL;DR: In this article, the authors investigated experimentally the hydrodynamic performance of floating breakwaters with and without pneumatic chambers, and they showed that the installation of the pnumatic chambers significantly enhanced the wave energy dissipation as well as reduced the wave transmission.

TL;DR: In this paper, system identification techniques (extended Kalman filtering and constrained least square method using generalized reduced gradient algorithm) are used to predict the maneuvering coefficients from several EFD, systems based and CFD free-running trials.

TL;DR: In this paper, the NREL 5MW turbine and the Dogger Bank site, in the North Sea, were investigated and compared through a preliminary techno-economic analysis, and the optimum concept among the seven, the tri-floater configuration, has been further developed and refined through hydrostatic, hydrodynamic, and structural analyses.

TL;DR: In this article, a new definition of a ship-ship collision criterion, called the minimum distance to collision (MDTC), is proposed, which is defined by means of a series of simulations using a ship motion model for a range of ship types, courses and speeds.

TL;DR: In this paper, a one-dimensional numerical model using Boussinesq-type equations including porosity of vegetation and its drag and inertia forces was developed to investigate the tsunami mitigation effects of vegetation in a forest model.

TL;DR: A novel algorithm for open-sea visual maritime surveillance that detects, localizes, and tracks ships in the field of view of the camera, uniquely designed to handle rapidly moving camera.

TL;DR: In this article, the authors deal with numerical methodology to model and study the bubble dynamics produced by an underwater explosion when it occurs in infinite medium, i.e. no interaction with any surrounding obstacle as the free surface, the seabed or deformable structures (surface ship or submarine).

TL;DR: In this paper, an uncoupled method combining Wagner theory and the finite element method is presented to analyze the slamming load and response of one complex 3D steel wedge with deadrise angle 22°.

TL;DR: In this article, a new analytical solution for water wave scattering by a submerged horizontal porous plate breakwater with finite thickness was given in the context of linear potential theory, where the original velocity potential was split into a symmetric part and an antisymmetric part.

TL;DR: In this paper, a pre-filter based sliding mode approach is proposed to control the steering system in ocean-going vessels, and the stability conditions of vessel steering in linear and nonlinear mathematical formations are analyzed.

TL;DR: In this article, the authors investigated the settlement behavior of a square piled raft in clay soil using numerical analysis and quantified the reduction of the average and differential settlements in soft and stiff clay soils.

TL;DR: Boundary element hydrodynamic calculations carried out on simple three-member arrays are shown to be consistent with these theoretical proofs and some aspects of the behaviour of the arrays are investigated.

TL;DR: In this paper, the wave-induced setups/setdowns and wave height changes over various fringing reef profiles were analyzed using an empirical eddy viscosity model to account for wave breaking and a shock-capturing finite volume solver was employed to ensure the computational accuracy and stability for steep reef faces and shallow reef flats.

TL;DR: In this paper, an experimental study on Vortex-Induced Motion (VIM) of the semi-submersible platform concept with four square columns is presented, which includes in-line, transverse and yaw motions, as well as combined motions in the XY plane, drag and lift forces and spectral analysis.

TL;DR: The proposed wavelet model (WLNN) that makes use of multiresolution time series as input, allows for more accurate and consistent predictions with respect to classical ANN models.

TL;DR: In this article, a dynamic model of a ship-mounted container crane (called the "mobile harbor") subject to the motions of ship itself imparted by random sea waves is investigated, and the condition of the sea is assumed to be State 3.

TL;DR: In this paper, a composite marine propeller was optimized to reduce vibration and dynamic stress by using the finite element method (FEM) coupled with computational fluid dynamics (CFD) in a non-uniform wake.

TL;DR: In this article, a failure envelope is proposed, allowing axial and normal interaction forces to be estimated for any angle of attack of the debris flow, rather than combining them into a single drag force.

TL;DR: In this article, a multiobjective optimization algorithm was applied to the design of a CPP propeller at different pitch settings, with the aim of reducing the cavitating phenomena and, consequently, the resultant radiated noise.

TL;DR: In this article, a finite element model based on linear wave theory has been developed to study scattered waves around single and multiple oscillating water column wave energy conversion devices, and the power capture efficiency of a single cylindrical OWC was compared with that of an array of OWCs, as a function of array spacing, pneumatic damping and direction of the incident waves.