There has been a significant increase in the number of published tidal-stream energy resource assessments in recent years due to the growing availability of open-source hydrodynamic models, and freely available data for model bathymetry (e.g. GEBCO_2014 and ETOPO) and boundary conditions (e.g. TPXO, FES, EOT). This study examines how the choice of bathymetry and tidal constituents affects the quantification

In this study, a two-phase flow solver with phase change is improved with considering the compressibility and is implemented in the open source software OpenFOAM. The thermal effect between water and vapor is ignored and the barotropic fluid hypothesis is used to close the system of Navier-Stokes equations. The finite volume method (FVM) is utilized for discretization and the volume of fluid (VOF)

Subjected to complicated and cyclical dynamic loads caused by waves, currents and vessel motions and transferred by drilling risers, the subsea wellhead (SW) is prone to fatigue failure, which could lead to the loss of well integrity and even catastrophic accidents. This paper presented a novel semi-decoupled model based local stress-strain approach to predict the fatigue damage of SW. Using the proposed

Stability is an important issue for the application of kinetic energy supercavitating vehicles. Interactions of supercavitating vehicles with their fluid environment are exceptionally complex. Traditionally, the kinetic modeling is established in the longitudinal plane, which is inevitable to lose some important features of 6DOF dynamic system. On the basis of general dynamics theory, a 6DOF dynamic

Remote sensing is a desirable method for measuring ocean currents on various spatial and temporal scales. Coastal acoustic tomography (CAT) can measure current velocity in coastal and shallow seas, but the application of this method in stratified shallow estuaries has not been sufficiently tested. This study revisits the acoustic transmission data obtained from the 2013 Hiroshima Bay CAT experiment

During the last decades, the detection of damages in offshore platforms has been one of the most important issues in ocean engineering. To achieve the goal of the accurate identification of structural damages, the damage-sensitive features need to be extracted from the structural dynamic responses. However, it is well known that the changes in the structural dynamic responses do not depend only on

Ship performance in level ice involves problems such as attainable speed and maneuverability under different ice thickness. As the alternative to analytical methods, numerical simulation models have been proposed in recent years to improve the accuracy and to analyze more complex operations. However, current numerical models use quite diverse approaches to model the icebreaking components, and focus

The significance and complexity of cyclic behavior of saturated silt under non-proportional loading are still of great concern in practice, due to the highly inherent anisotropy of soil fabric. This paper presents an experimental investigation conducted in an automated hollow cylinder apparatus into the undrained anisotropy and cyclic resistance of a saturated marine silt under wave-induced non-proportional

Autonomous underwater vehicles (AUVs) are important tools for topography mapping and geological surveys, and bathymetric simultaneous localization and mapping (BSLAM) method holds high potential for accurate navigation in long endurance AUV missions. However, invalid loop closures caused by nearly flat seabed topography may cause BSLAM algorithm fail catastrophically. In this paper, a robust BSLAM

The structural fatigue damage caused by vortex-induced vibration (VIV) is one of the most important failure reasons for flexible cylinders in offshore engineering applications. Helical strakes are often employed to reduce the VIV of slender marine structures. Based on a previous experimental investigation, this paper further investigates the effects of the yaw angle on the VIV fatigue damage of a yawed

The motion performance of underwater gliders (UGs) is an important basis for their preliminary design. Because of their unique buoyancy-driven mode, the UGs differ greatly in dynamic model and working principle from the propeller-driven underwater vehicles, such as submarines, torpedoes and autonomous underwater vehicles (AUVs). Therefore, it's inadvisable to use the evaluation models and criteria

The aim of this work is to analyze the performance of the Overtopping Breakwater for Energy Conversion (OBREC), developed by the team of the University of Campania and installed at prototype scale in the port of Naples. It is a multifunctional coastal structure aimed to protect harbors and produce energy, based on the overtopping principle. This device has been preliminary analyzed by means of experimental

To obtain a maximum power output and minimized capital and operational costs, the layout of wave energy parks needs to be optimally designed. An economical model for large-scale wave energy systems is built and merged into an evolutionary optimization routine for arrays of point-absorbing energy converters. The model includes all the parameters that affect the total system revenue such as electrical

Human support and the inevitable interaction necessarily play a major part in daily production and maintenance activities on offshore platforms, thereby immensely affecting the performance of workers owing to the harsh working environment. Unsurprisingly, 75% of fire and explosion accidents are caused by human error [1–5] and it is mostly in combination with other causes. On offshore platforms, one

This paper describes an investigation of the motion, structural response, and cavitation bubble evolution of a cylinder in the high-speed water entry (HSWE) process using a fluid-structure interaction (FSI) method. The effectiveness and accuracy of the FSI method are verified by comparison with experimental results available in the literature. The results show that the cylinder structure is deformed

The thrust performance of a two-dimensional plate pitching harmonically in a uniform flow is assessed numerically using the OpenFOAM toolbox [1]. The mesh displacement vector associated with the rigid body motion is computed as the solution of a Laplace equation with variable diffusivity, using the appropriate mesh manipulation class of the toolbox. For a Reynolds number of 2000, the accuracy of the

The emphasis of this work is on comparison of fatigue damage capacity at the bulkhead and web frame connections of side shell longitudinals under the effect of vertical and horizontal bending in combination. Fatigue analysis methods adopted such as component stochastic and full spectral consider an FPSO of 325 m length, selecting side shell longitudinal structural elements connected to the typical

The hydrodynamic performance of tandem propeller (two co-rotating KP458 propellers) is investigated by an FVM (Finite Volume Method) based approach in this study. The effects of advance ratio J (0 ≤ J ≤ 0.7), spacing ratio (0.26 ≤ L/Df ≤ 0.34) and diameter ratio (0.92 ≤ Da/Df ≤ 0.97) are comprehensively studied and analyzed. A three-dimensional cubic computational domain is considered in this study

This paper proposed a path following controller for the unmanned surface vessel (USV) by taking advantage of the vector field (VF) guidance method and the characteristic model-based heading angle and speed tracking approach. Considering the fact that the motions of USVs without professional design were difficult to be accurately modeled due to the high complexity in terms of nonlinearity and coupling

Ships and offshore structures are exposed to various cyclic loads such as winds, waves and currents in their lifetime. These loads can result in fatigue failures at hot spots, and so to prevent such failures, accurate estimates of the fatigue life of hot spots should be performed in the design stage. The cycle distribution indicative of the probability distribution of cycles is an important factor

The three-dimensional Green-function method is presented in this paper to predict the water wave radiation of a submerged body in infinite depth of water with ice cover. The ice is modelled as an elastic plate and the fluid is assumed to be perfect fluid and irrotational. The zero-speed Green function satisfying the linearized covered-surface condition is derived for the first time in three dimensions

In this study, a time-domain hydro-elastic model is developed to solve the floater-connector-mooring coupled system. The frequency-domain model is first devised with the discrete-modulus-based method in which the deformable floating structure is modeled with multiple rigid bodies connected by high-order beam elements. The corresponding multi-body hydrodynamic coefficients and loads are estimated by

In this work, the morphodynamic response of microtidal dissipative and reflective beaches to extreme wave events generated by hurricanes and cold fronts in the Colombian Caribbean was established. Two sandy beaches were used as case studies, Bocagrande (Cartagena, Bolívar Department) (dissipative) and Costa Verde (Ciénaga, Magdalena Department) (intermediate–reflective). The numerical models SWAN and

Cargo transshipment operations between large vessels are increasingly recurrent in the oil and gas industry scenario. Due to the operational limitations of Brazilian terminals and ports and recent discoveries of large oil and gas offshore fields in the pre-salt area, new types of configurations are being studied to propose alternatives for operators. The present work proposes a methodology for the

In this paper, a nonlinear Timoshenko beam model is considered to analytically investigate post-buckling and nonlinear vibration of flexible fluid-conveying pipes made of functionally graded materials. Closed-form expressions are presented to study the effects of shear deformation and rotary inertia on the post-buckling behavior and nonlinear vibration of fluid-conveying functionally graded pipes for

This paper aims to provide stable landing methods and systems for hovering-type AUVs (autonomous underwater vehicles) on a seafloor, which will aid in seafloor investigations, such as gravity acceleration measurements near the seafloor. The proposed methods consist of two techniques. Firstly, a heading control method is proposed, in which the AUV is positioned to face currents before landing on the

The characteristics of an evolving ocean surface wavefield under tropical cyclone Hudhud that took place in October 2014 are investigated. The Hilbert-Huang transformation (HHT) is used for the spectral analysis of the cyclone generated waves. Empirical mode decomposition (EMD) is used to decompose the wave data into different intrinsic mode function (IMF). Hilbert Marginal Spectra and the Fourier

The integration of a dual sphere wave energy converter with a chambered breakwater system is found to enhance the performance of both structures. Such an integrated system is well suited for regions that receive medium wave energy potential at an estimated annual mean wave power less than 30 kW/m. The hydrodynamic efficiency of the integrated system is investigated through experiments. The dual sphere

The potential of artificial upwelling (AU) in enhancing transport of nutrient-rich bottom water to the surface, stimulating seaweed growth and consequently increasing organic carbon removal from coastal waters to land after harvest has attracted increasing scientific interest. This practice, however, hardly have field experiments to confirm the hypothesis. The coastal mariculture environment requires

In the marine and ocean engineering area, the water-entry process is a typical problem of fluid-solid interaction, which involves complex phenomenon such as the large deformation of free surface and considerable structure movement. In this process, the predicting impact load and summarizing the evolution law of the free surface deformation have important reference significance for the hull structure

The small heeling floating condition caused by asymmetry buoyancy is high possibility to happen during the trimaran voyage. In order to observe the characteristic of trimaran seakeeping performance and load response in small heeling condition, the segmented model and corresponding monitoring scheme is designed in detail. A series of model tests were conducted to measure motion and wave-induced load

In the present study, gravity wave interaction with a wave attenuating system (WAS) comprised of a series of surface piercing thin vertical porous plates fixed on a fully submerged rigid pontoon is analyzed. For the wave past porous barriers, a quadratic pressure drop is considered to account for the energy dissipation due to changes in wave steepness. A numerical model based on iterative multi-domain

Water wave interaction with a submerged perforated quarter-circular caisson breakwater is investigated in this study. Based on linear potential theory, analytical solutions of the problem are developed for normally and obliquely incident waves, respectively. In the solving procedure, the entire fluid domain is divided into an external region and two quarter-circular inner regions. The series solutions

The effects of finite-span computational domain with periodic boundaries for vortex-induced vibration simulations are investigated. Coupled fluid-solid dynamics of an elastically-mounted rigid circular cylinder are performed using detached eddy simulations with four computational domains of different span lengths. Simulations with span less than five-cylinder diameters give erroneous results including

Maritime traffic route is the basis for the analysis of ship traffic characteristics and navigation safety. However, the spatial freedom of ship navigation makes the extraction of maritime traffic route a challenging task. In order to realize the extraction of ship traffic routes at sea, a maritime route extraction method based on ship history automatic identification system (AIS) data is proposed

The parametric resonance in roll motion (known shortly as parametric roll) was studied for a fishing vessel in regular waves. This is an instability and resonance phenomenon that can lead the roll to reach very high oscillation amplitudes at its natural frequency, depending on the damping level involved. In the worst cases it is responsible for vessel capsize. Here the problem was investigated numerically

The hydrodynamic problem of a three dimensional cone entering water in three degrees of freedom is analysed based on the incompressible velocity potential theory. The effect of horizontal motion and rotational motion on the entry process is investigated. The problem is solved through the boundary element method in the time domain. Two physical coordinate systems are constructed. One is the body-fixed

Accurate prediction of wave loads on ships and floating structures is paramount in the structural design stage. Use of a segmented ship model is a common method to quantify the wave loads. Nevertheless, the value could be measured only at segmented sections. To obtain the wave loads at any longitudinal position and to account for nonlinear features in the wave loads more precisely, local quantities

In vibration-based structural health monitoring (SHM), if the data are collected at a higher sampling rate from sensors, a large amount of computing resources and space resources will be consumed. For offshore platforms with limited space resources, there are many difficulties in long-term continuous monitoring. Aiming at this problem, the influence of sampling rate on structural damage identification

Mesoscale eddies regulate oceanic material transport and atmospheric current. The area around Xisha Islands is an important sink region for mesoscale eddies. We observed two cyclones during September to October 2019, and found that these two cold eddies had split from one local cold eddy. Using a Chinese Autonomous Underwater Vehicle(AUV), called ‘Sea-Whale 2000’, for field experiment, we successfully

Ring stiffened cylindrical shells find wide applications in marine vehicles such as submersibles, submarine, autonomous underwater vehicles (AUV) and torpedoes. The structures used for military applications are susceptible to shock loadings from an underwater explosion. It is imperative to understand the shock damage mechanism of such structures to design for survivability. The problem is quite complex

This article develops novel analytical solutions to oblique wave scattering by porous rubble-mound structures based on linear potential theory. The novelty of the solutions is that the usual complex root finding algorithm is avoided by applying a contour integral technique. In the solving procedure, the whole fluid domain is divided into multiple regions, and the series solution of the velocity potential

The Boussinesq-type equations in terms of velocity potential are adopted for the solutions of three-dimensional nonlinear sloshing motions in a shallow-water rectangular tank. The total velocity potential is divided into two parts: a particular solution and the rest which is calculated by the Boussinesq-type equations. Particular solutions of six degrees of freedom motions are constructed. The fully

Flat plate models of fixed aspect ratio incorporating either serrations or holes at the upper and lower plate edges, were towed normal to the flow and in proximity to the free surface. The hydrodynamics and the drag generated by the plates has been studied in detail for several configurations. In general, the models with holes presented greater drag reduction than those with serrations, with the hole

As a marine renewable resource, ocean thermal energy conversion (OTEC) is gaining attention because of its sustainability and environment-friendly characteristics. The thermal energy potential in the open ocean has been well documented in the previous literature. However, regional potential near the coast is not easily estimated using methods and parameters for global estimation. This study estimates

This paper is concerned with a study on monsoon wave transmission at bamboo fences protecting newly-planted mangroves in the Lower Mekong Delta (LMD) of Vietnam. For this, new field experiments were carried out in combination with the use of an existing field dataset by Albers et al. (2013). In support of the analysis of the field data, influences of governing parameters on wave transmission are systematically

In the complex Ocean environment, wind load is the most important factor that should be addressed in the design of jack-up platforms. Although many efforts have been made to analyze the dynamics of jack-up platforms considering wind load effect, literature review shows that very limited work has been done to address the calculation of the wind load coefficient of each individual key component in a

The critical suction pressure will lead to the difference in equivalent overburdens at the skirt-tip level between outside and inside the caisson exceeds Ncrsu (Ncr is the local reverse bearing capacity factor, and su is the undrained shear strength of clay at the skirt-tip), which may induce the local reverse bearing capacity failure of soil near the skirt-tip. As a result, soil flows into the caisson

It has been observed and theoretically proved that edge waves can be generated by a moving atmospheric pressure disturbance near the coast. This study aims to clarify the necessary conditions for the occurrence of significant edge waves associating with moving atmospheric pressure disturbances. The complex physical problem is simplified as a pressure disturbance moving along a coast with a constant

This paper presents a bivariate regional frequency analysis applied to vectors of extreme significant wave heights and concurrent zero up-crossing wave period over an area in the North Atlantic ocean. The analysis is based on a bivariate index-wave/period approach and the assumption of a common regional growth curve within homogeneous regions. The main benefits of performing a regional frequency analysis

A deep insight into wake of a tidal stream turbine can be essential to make tidal stream energy commercially viable. This study is to experimentally investigate downstream field of a horizontal axis tidal stream turbine supported by a mono pile. Two scenarios with and without a rotor are considered and compared with each other in this study. An advanced Acoustic Doppler Velocimeteris employed to measure

Large eddy simulation (LES) was used to simulate turbulent cavitating flow around a conventional marine propeller (CP) and a highly skewed marine propeller (HSP) with emphasis on the skew angles effects. The LES verification and validation (V&V) analysis was carried out with cavitation influence on the flow structures. The current numerical results demonstrate that LES can give excellent predictions

Long-term shipboard measurements of vessel performance in actual seas and practical guidance for proper ship operations in rough sea conditions are of great importance for a safe, economical and environment-friendly optimum ship routing. Data was collected from a bulk carrier during 2010–2016 covering both the Southern and Northern Hemispheres with high seasonal variability. Using the meteorological

Marine structures are exposed to various destructive factors during their serviceability. Therefore, timely damage detection and repair of these structures at early stages can increase their service life and prevent economic and human losses as much as possible. In this study, a method is presented to identify the location of multiple damages in the piles of a dolphin pier. In the first step of the

The formation of multiple AUVs in a row during navigation can effectively improve energy efficiency and detection capability. Since it is difficult to assign multiple AUVs to form a row efficiently, the optimal assignment in operations research is innovatively used to solve this problem in this paper. However, due to the limited data processing capability of the AUV and its trajectory being disturbed

The control of Autonomous Underwater Vehicle (AUV) is considered as a challenging problem, mainly due to the AUV's nonlinear and uncertain dynamics. In fact, the underwater vehicles require a robust control scheme in order to maneuver to any given point and track a moving target regardless of external disturbances. The main aim of this work consists of proposing two different designs of a robust control

Although the load transfer curves (i.e., p-y curves) recommended by the current industry standards are regarded as questionable for the recently emerging large diameter monopile, the influence of pile diameter and bending stiffness on the p-y curves in sand has not been systematically quantified. Nor have the underlying mechanisms of the diameter dependent p-y curves been well understood. This study

With climate changes and global warming, the extent of Marginal Ice Zone (MIZ) in the polar region is widening, and there is now more research attention on the wave interactions with broken ice covers within the zone to gain insights into its future sea conditions. Towards this objective, the dispersion and attenuation of surface waves propagating through segmented floating viscoelastic covers was

Risk analysis is of paramount importance in maritime transportation due to the nature of work. The IMO (International Maritime Organization) adopted FSA (Formal Safety Assessment) as guidance to address risk analysis on-board ship. However, it does not suggest a specific approach on how to assess the risks. Therefore, safety researchers are seeking robust risk analysis approaches in maritime transportation