Understanding the risk of collision between tidal stream turbines and marine species is required for environmental impact assessment. Field observations are often limited by sensor capabilities. This study used a laboratory-scale water tank to monitor fine-scale fish behavior near a model of rotating turbine blades. Differences in behavior between three species were investigated: Oryzias latipes, Gnathopogon

This study presents a new mathematical hull-form that is expressed as an explicit function with 10 hull-form parameters, which is called the Matsui hull-form in this study. The proposed hull-form was developed by expanding the modified Wigley hull-form so that the following 10 hull-form parameters can be independently varied: main dimensions \(L\), \(B\), \(d\), fineness coefficients \({C}_{b}\),

Previous studies of analysis and prediction of marine risers responses usually focus on vortex-induced vibration (VIV) of cross-flow (CF) direction rather than in-line (IL). Recent studies show that responses of IL direction tend to dominate in some cases. Responses of long riser due to biaxial bending of IL and CF VIV are investigated. Closed-form formulas are derived for estimating maximum normal

This paper aims to investigate the nonlinear dynamic response of steel steep wave risers (SSWRs) considering the excitation of internal solitary waves (ISWs). Considering ISWs and the combined excitation of vessel motion (VM), surface wave (SW), this paper proposes a three-dimensional nonlinear dynamic model of the SSWRs based on the slender rod model. The finite element method and the Newmark-β method

Nonlinear model predictive control (NMPC) has become a preferred option particularly for controlling a strongly nonlinear system due to an increase in the availability of powerful cheap computing resources in recent years. However, there are still some hurdles to widely apply the NMPC algorithm for fast nonlinear dynamic systems. One of the primary challenges is how to quickly solve a set of nonlinear

With the development of modern military and civil aviation and navigation, the research on the impact load characteristics of water has an important engineering application background. To further study the calculation of water–air interface load characteristics, a load calculation formula on the basis of test data is proposed, and the influence of water entry curvature on load characteristics are analyzed

Multibeam bathymetric system (MBS) has been widely applied in marine exploration activities for providing high-precision seafloor topography. However, the representative error of sound velocity profile (SVP) can degrade the precision of sounding and lead to the distortion of seafloor topography. To resolve this problem, we propose a seafloor topography distortion correction method based on the SVP

The study investigates the tethered underwater robot's maneuverability and hydrodynamic performance in a uniform flow field. A tethered underwater robot that installs a symmetrically Ka 4–70/19A ducted propellers and vertical rudder is first constructed to simulate the motion. The numerical simulation is based on the multiples computational fluid dynamics (CFD) techniques, such as overlapping grid

The present paper introduces a mathematical model applicable to force and torque prediction on a rudder in behind hull/propeller conditions for a ship performing manoeuvres in a harbour. The latter implies a full 360° possible inflow direction to the rudder, combined with propeller rates ahead or astern. The mathematical model coefficients were derived based on a captive model test campaign performed

Given that the items and bins have random sizes, the optimization of pipe cutting in offshore platform construction can be described as a variant of the variable-sized bin-packing problem. In this study, we propose a hybrid algorithm (HCHACO) that embeds a constructive heuristic based on the combined approach in the modified ant colony optimization (ACO) scheme to solve this problem. The combined approach

In this paper, a robust adaptive control scheme is proposed for the trajectory tracking control of underactuated surface vessels (USVs) subject to unknown dynamics, external disturbances and input saturation. First, a coordinate transformation is introduced to deal with the underactuation problem of the USV. A Gaussian error function and an adaptive neural network (NN) are adopted to approximate the

This paper addresses a spectral approach for evaluating the fatigue damage in a floating offshore wind turbine (FOWT) structure accurately by taking account of the nonlinear coupling effects between wind and wave loads. It is shown that the spectral moments under the combined loads can be estimated by a sum of those under wind-only cases and wave only-cases, however, with some corrections to account

The study of several problems to determine the width of the coastal area of navigation for the vessel and the determination of the parameters of the vessel, capable of moving against the wave in the coastal area, was proposed in this article. A method was developed based on solving an inequality that includes the kinetic energy of a ship with added masses of water and wave energy. A formula and a graph

This study investigates the competitiveness of various autonomous ship categories for container shipping in the Arctic route. We propose a multi-criteria decision-making (MCDM) framework using four ship categories as alternatives and eight criteria for competitiveness evaluation. We analyse collected data using the Best–Worst Method (BWM), one of the recently developed MCDM methods. The findings reveal

In this work, the scale effects on the open water performance of a pump-jet propulsor (PJP) with pre-swirl stator are considered and implemented based on systematic numerical calculations. With considering the effects of mesh density and time-step size, the unsteady open water performance at the design advance coefficient both in full scale and model scale is first discussed. Then, the scale effects

Ocean thermal energy conversion (OTEC) is a power generation technology that extracts energy from the temperature difference between deep seawater and surface water in the ocean. Currently, a 100 kW class OTEC demonstration project is underway on Kume Island, Okinawa, and a plan to increase water intake and introduce a 1 MW class OTEC plant is under consideration. Year-round generation of electricity

The human factor is a hot topic for the maritime industry since more than 80 percent of maritime accidents are due to human error. Minimizing human error contributions in maritime transportation is vital to enhance safety levels. At this point, the maritime autonomous surface ships (MASS) concept has become one of the most significant aspects to minimize human errors. The objective of this research

For accurately evaluating the risk of broaching for a ship in stern quartering waves, the wave forces calculated with a slender body theory under the low encounter frequency assumption are often corrected empirically with the help of captive model experiment or computational fluid mechanics (CFD). However, the hydrodynamic explanation of such empirical correction was not sufficient so far. Thus, this

Taut moorings have become a prospective solution for keeping associated stations of floating production systems stationary. For most taut mooring lines, the uplift angle at the padeye of the anchor can reach up to 40°. To withstand this vertical load, embedded anchors are widely employed with the padeye some distance below the mud-line, causing part of the bottom chain to be embedded in the soil. This

Today, due to the complexity of systems and interactions among their subsystems, the design optimization of a system is highly difficult and costly. Multidisciplinary optimization is an approach, in which interactions among different disciplines are taken into account, and it attempts to optimize all disciplines, simultaneously. In the design process of a system, there is usually some uncertainty in

An efficient crack propagation (CP) simulation system based on a shell-solid finite element (FE) modeling is newly established. Three-dimensional (3D) CP simulation for a curvilinearly propagating surface crack in a steel circular hollow section (CHS) T-joint is carried out. Entire model is generated by a shell FEs, and cracked welded part is generated by a solid FEs. They are connected with a rigid

The analysis and understanding of the complex behaviour of a ship propulsion plant are of great importance for novel system design, control system synthesis/optimization and to sustain the safety of ship operation in harsh sea conditions. The convenient way to evaluate the design and propulsion performance of a ship in waves is by simulation combining the experimentally obtained characteristics of

Numerical simulations of underwater vehicle wake flow field and propeller excitation force were performed to evaluate the performance of the k-ω SST RANS and k-ω IDDES turbulence models. First, the nominal wake of the SUBOFF model and open water characteristics of the INSEAN E1619 propeller were compared to the experimental measurements to validate the numerical method. Then, the flow field around

Deterministic sea wave prediction (DSWP) provides an effective way of predicting time history for a fixed point or spatial wave elevation on a fixed snapshot. DSWP models are realized by assimilating various phase-resolved wave models and measured wave data. For a given prediction accuracy level, the predictable zone is affected by the distance between the measurement and forecasting locations, the

This note focuses on the leader–follower formation control problem of underactuated surface vehicles (USVs) with the unknown environmental disturbance. Especially, due to the ocean environmental disturbance, the vehicle’s desired-heading angle is altered violently. To address the constraint, a reduced-order extended state observer (ESO) is introduced. The sideslip angle of the vehicle is estimated

The propulsion shafting is one of the main excitation sources of ship vibration and noise. Thus, shafting vibration and alignment are very important issues in the design of a propulsion system. In the present paper, the effects of shafting alignment on shafting whirling and bearing vibrations will be discussed. This study has been carried out experimentally on a test rig designed by the Wuhan University

Using the stochastic averaging method, the probability density function (PDF) of roll motion for parametric rolling in irregular waves is obtained. In this paper, the stochastic averaging method using Hamiltonian proposed by Dostal is used, and the PDF of roll amplitude and Hamiltonian are derived from the equations of roll motion. In addition, the asymptotic behavior of PDF is investigated to improve

In this research, a camber changing mechanism feasible for use in a flapping hydrofoil tidal stream turbine is suggested to generate high lift force and subsequently a large flapping angle as a dynamic response. The hydrodynamic characteristics of rigid and variable-camber hydrofoils, which mainly affect the response, were numerically obtained using XFOIL. The flapping responses of the hydrofoils were

Trajectory planning is one of the important technologies to ensure the safe navigation of the unmanned ship. This paper presents a dynamic path planning method based on the multi-layer Morphin adaptive search tree algorithm, which considers ship maneuverability, COLREGS, and good seamanship to harmonize the actions in the mixed traffic environment. First, the environment model is built according to

The time derivative of acceleration is called a jerk, which is an important property to evaluate ride comfort in elevators, cars, and so on. Likewise, evaluation of motion sickness or ride comfort on a vessel could be achieved by this jerk property in the future. In this paper, we utilize the PDF Line Integral Method (PLIM), which was newly contrived in our previous research, for calculating not only

This paper proposes a novel system identification scheme to obtain a MIMO model of ship maneuvering motion, which can leverage the temporal correlation from the constructed training data to learn the underlying feasible model robust to extraneous noise. The scheme is based on long–short-term-memory (LSTM) deep neural network, which is more easily trained than traditional feedforward neural network

A correction to this paper has been published: https://doi.org/10.1007/s00773-021-00821-1

When waves from two weather systems converge at a certain sea area, cross waves can be produced. It is important to have a better understanding of the motion characteristics of ship in cross sea to ensure its navigation safety. In this paper, the motion responses of a S175 container ship hull in cross sea is first analyzed based on CFD technique using RANS method. VOF method is used to model and capture

Current guidelines for approval of autonomous ship systems are focused on the ships’ concrete operations and their geographic area. This is a natural consequence of the link between geography and the navigational complexity, but moving the ship to a new area or changing owners may require a costly re-approval. The automotive industry has introduced the Operational Design Domain (ODD) that can be used

With the development of deep-sea oil and gas resources, the aspect ratio of deep-sea flexible riser has reached the order of 102–103, which makes the experimental model of the equal scale of deep-sea flexible risers challenging to achieve under typical experimental conditions. Alternatively, the non-scale experiment is sometimes used. However, the dynamic response of the prototype may not be exactly

There are typically unknown deviation tides and stochastic measurement errors in digital elevation map and real-time measurement terrain map, which result in the failure of the matching algorithm. To address the problem of the robust terrain-aided position under the condition of unknown tidal and measurement errors, a new terrain-aided position (TAP) model and a tide level estimation method based on

A methodology for predicting the probability density function of roll motion for irregular beam seas is developed in the author’s previous research. In this paper, two methods for the prediction of the probability density function (PDF) of the rolling amplitude are examined. One of these methods is an approach based on a non-Gaussian PDF with the use of the equivalent linearization and the moment method

The coupled motion of roll and pitch is noticeable when trimaran sails in oblique head waves, which will lead to negative influence on the safety and comfort of navigation. In this paper, the numerical simulation of the trimaran's motion in oblique waves was carried out by open source CFD tool OpenFOAM, and the computed motion response was analyzed to study the characteristics of the torsional rolling

Thrust allocation is of great importance for the application of Dynamic Positioning System (DPS). For dynamically positioned vessels, the thrust allocation is formulated as a nonlinear optimization problem, where the demanded forces and moments are distributed among the available thrusters. Both hydrodynamic interaction effects and physical limitations of thrusters affect the thrust generation. Therefore

This paper proposes a hybrid robust-adaptive learning-based control scheme based on Approximate Dynamic Programming (ADP) for the tracking control of autonomous ship maneuvering. We adopt a Time-Delay Control (TDC) approach, which is known as a simple, practical, model free and roughly robust strategy, combined with an Actor-Critic Approximate Dynamic Programming (ACADP) algorithm as an adaptive part

The development of an offshore deepwater oilfield is a complex and risky task. One core problem in this project is the selection of a production system that maximizes oil recovery and minimizes investment and operational costs while meeting external, economic, environmental, societal and technological demands under a scenario of uncertainties. Although several studies address this problem in the literature

The result from a multi-objective optimization on the outlet diffuser angle of the tidal turbine is presented with a focus on the turbine efficiency and cavitation. This study is the first to investigate the impact of the diffuser angle on the diffuser augmented tidal turbine in performance and cavitation inception. The 1/2 scale model was designed with three blades based on NACA 4616 airfoil. Seven

Understanding the complex flow fields behind the propeller and the structure of vortex shedding of cycloidal propellers are essential to analyzing the instantaneous forces on the blades and the overall hydrodynamic performance. In this paper, numerical simulation is performed to investigate the hydrodynamics and vortex shedding of cycloidal blades. The numerical results agree well with experimental

A correction to this paper has been published: https://doi.org/10.1007/s00773-021-00806-0

Trends of large-scale ships have seen propulsion shaft and propeller sizes increase. This has enabled shafts to have greater stiffness, yet has caused flexibility to lessen and induce bearing failure at the aft stern tube bearing. In general, shaft alignment is calculated and evaluated in accordance with classification societies’ rule requirements. Especially, positioning reaction support and stiffness

A correction to this paper has been published: https://doi.org/10.1007/s00773-021-00807-z

A novel numerical method combining Eigenfunction matching method (EMM) and 3D Rankine source method is developed to investigate wave-body interaction over a sloping bottom. The extended EMM is proposed to create an incident wave model over the sloping bottom, thereby obtaining the Froude-Krylov force and Neumann data on wet surfaces of the floating body for the diffraction problem. A 3D Rankine source

To minimize the energy consumption of contra-rotating propellers (CRPs), the optimal matched rotational speeds of the forward propeller (FP) and rear propeller (RP) of CRP are investigated based on the potential-based panel method. The optimal matching problem of a set of CRP405 is investigated. The open-water hydrodynamic performances of CRP405 with the FP and RP having the same rotational speed are

Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH) method are effective methods to study the interaction between marine structures and sea ice. However, both FEM and SPH methods have their own shortcomings in numerical simulations. There are mesh distortions and disappearance in FEM, and tensile instability, difficulty in applying boundary conditions, and low computational efficiency

This paper presents the flow-induced forces over 3-column arrays with different cross-sectional geometries due to the current incidence only, using Computational Fluid Dynamics (CFD) calculations for a low Reynolds number (\(\mathrm{Re}\)). The flow around circular, square, and diamond sections of 3-column arrays was evaluated for stationary conditions (i.e., with no degrees of freedom). These analyses

A numerical model considering the seabed friction is developed to investigate the dynamic behavior of anchor cable in this paper. In the model, the anchor cable was divided into hanging and lying parts. The governing equations of hanging and lying anchor cables were established respectively based on finite difference method and coupled according to the boundary conditions. The coupled equations of

Fuel consumption is an important factor to be considered in the process of weather routing. How to choose an appropriate route according to the requirements is particularly important. This paper proposes a method to optimize the ship weather routing. Based on the original genetic algorithm, the trigonometric function selection operator is introduced, the mutation operator is improved to increase the

Wind propulsion for commercial ships has been identified as a key component in the energy transition for the maritime industry. The sailing hybrid ship will operate with leeway (drift) angles to produce a lateral force known as sideforce, for steady operation under sail. In this paper, experimental results for the sailing performance of ships fitted with bilge keel appendages are presented. Systematic

Since large heave and pitch motions of a high-speed multihull seriously affect the navigability of the ship, it is significant to design the effective anti-pitching control for the multihull. However, the existing anti-pitching controllers are all designed based on deterministic dynamics models and have disadvantages of low control robustness, high dependence on experience, high complexity and low

Artificial intelligence is an enabling technology for autonomous surface vehicles, with methods such as evolutionary algorithms, artificial potential fields, fast marching methods, and many others becoming increasingly popular for solving problems such as path planning and collision avoidance. However, there currently is no unified way to evaluate the performance of different algorithms, for example

In this study, a six degrees of freedom (6-DOF) motion simulation method of a ship steering in regular waves is validated. The proposed simulation model is based on the two-time scale concept where the 6-DOF motions are expressed as the sum of the low-frequency maneuvering motions and high-frequency wave-induced motions. Turning simulations of a KCS container ship model with a rudder angle of \(\pm

The rudder force, including interference with a ship hull in large drifting conditions, is investigated in this study by captive model tests using a ship model with steering. In the tests, hydrodynamic forces acting on the ship, the rudder normal force, and propeller thrust are measured while changing the hull drift angle \(\beta \) in the range of \(-180^{\circ } \sim 180^{\circ }\), which encompasses

Autonomous surface vehicles are gaining increasing attention worldwide due to the potential benefits of improving safety and efficiency. This has raised the interest in developing methods for path planning that can reduce the risk of collisions, groundings, and stranding accidents at sea, as well as costs and time expenditure. In this paper, we review guidance, and more specifically, path planning

When the ship speed exceeds a certain level in shallow water, ship-bank interaction induces great influence on the ship’s manoeurability with some special hydrodynamic characteristics, but the mechanism is not totally understood. This paper presents a numerical prediction of the ship-bank interaction for the model of the KRISO Container Ship. An unsteady Reynold-Averaged Navier Stokes solver is applied

In the presence of unknown environmental disturbances, this paper develops a robust adaptive synchronization navigation control design with prescribed performance for the supply ship during underway replenishment using the adaptive technique, the prescribed performance control (PPC) technique and the command-filtered backstepping approach. The adaptive law is derived to estimate the bounds of unknown