In this paper, a series of experimental data for wave (current)-induced pore-water pressure around a partially embedded monopile is presented. Unlike the previous studies, the combined action of waves and currents is studied. The partially embedded monopile is considered. The variations of pore-water pressures around the monopile in time and space are investigated by wave flume experiments. The experimental

This study proposes a hybrid surrogate modelling approach with the integration of deep learning algorithm long short-term memory (LSTM) to identify the mechanical responses of caisson foundations in marine soils. The LSTM based surrogate model is first trained based on limited results generated from the SPH-SIMSAND based numerical simulations with a strong validation, thereafter it is applied to predict

With the increasing popularity of wind energy, offshore wind turbines (OWTs) are currently experiencing rapid development. The tower is one of the most significant components of the OWT. However, the tower will not only stand its own weight and weight of the top structure, but also be surrounded by harsh wave and wind loading conditions. Therefore, it is necessary to apply a structural health monitoring

Spudcan foundations have been widely used in offshore oil and gas engineering for jack-up rigs. During penetration into seabed soil, spudcan foundations may encounter large uncertainties in soil properties, which have a strong impact on its bearing capacity. A large number of studies have been conducted to demonstrate the failure mechanisms and the bearing capacity of spudcan foundations in soils with

Physical experimental and 3D numerical free decay tests are performed for a stationary oscillating water column (OWC) device with various underwater opening heights and power take-off (PTO) mechanisms. Numerical model results are verified with experimental data. Equivalent linear damping of the system is found by using logarithmic decrement method. Natural and resonant frequencies and added mass are

This study addresses subsea search applications where an autonomous underwater vehicle (AUV) is tasked with finding the target density in a given search region within finite time. We assume that AUV is equipped with a side-scan sonar sensor that detects the targets at the sampled location. We consider that sensor performance is dependent on local environmental conditions (e.g., clutter density, sediment

Ocean waves contain one of the world's largest untapped and predictable renewable energy sources that can be used to fulfil the energy demand in the present energy crises situation. There are many devices that have been proposed and prototyped in different countries all around the world to harness wave energy based on different power take-off (PTO) systems. The aim of this article is to review the

Speed control in inland water systems needs to achieve effective balance between ship operational efficiency and transport safety. However, speed limit regulations are largely formulated through expert judgment rather than objective evidence-based evaluation, which sometimes leads to inefficiency due to subjective bias. In this study, a new method is proposed to evaluate the performance of shipping

Typical industry models for Offshore Wind Turbines with fixed substructures are based on decoupled models between the wind turbine and the substructure. It is proved that the complete dynamic response of the structure can only be captured with coupled models. In this paper a fully-coupled model for Offshore Wind Turbines with jacket support is presented. The computational model allows to obtain an

This paper investigates the relationship between bunker fuel consumption and the speed of container ships. Although there are different models existing in the literature and in the industry, they do not always seem to match the actual maritime conditions. The existing models work well in middle speed levels, but they fail at the low- and high-speed ends unless the parameters in the exponent of the

Improving the efficiency and power output of hydrokinetic turbines is critical to making them a viable and cost-effective renewable energy solution. Diffusing shrouds have already been shown to improve the performance of horizontal axis, axial-flow turbines. It has been suggested that adding pre-swirl stators to the shroud could alter the inlet flow so as to maximize net tangential force on the turbine

Flows at tidal-stream energy sites are characterised by high turbulence intensities and by the occurrence of highly energetic large and coherent flow structures. The interaction of the flow with seabed roughness is suspected to play a major role in the generation of such coherent flow structures. The problem is introduced with canonical wall-mounted square obstacles representing abrupt changes of bathymetry

Two common techniques in determining surface wave power include a full wave spectrum integration and a representative wave approach. Under the concept of spectral wave parameterization, a new estimation formula is introduced in this study to capitalize the advantages of both the numerical method and the closed-form solution. The formula was verified using synthetic wave data and its applicable condition

The in-pipe inspection robotic system is crucial in examining the inside of a pipe without compromising its structural safety. The in-pipe inspection robotic system is a promising alternative to conventional methods of x-ray inspection and visual inspection. Despite the ongoing investigation, the effectiveness of the in-pipe inspection robotic system, particularly regarding the mathematical modeling

The assessment of mesh resistance to opening is a key factor when coming to fishing gear design to study or optimize the fishing selectivity process. Different authors proposed methodologies to achieve twine flexural rigidity identification and mesh opening angle at rest. Their experimental protocols could rely on complex installations and instrumentation, and identification needs dedicated models

Ballast tank sediments host organisms that pose invasion risk even if the ships are installed with ballast treatment systems. The bottom sediments also contribute to corrosion and cause cumulative deadweight loss over the years. This study presents the outcomes of the project “Conceptual Ballast Tank Design for Reducing Sediment Accumulation” (TUBITAK, Grant No: 115Y740). In the published first phase

A low-cost Global Navigation Satellite System (GNSS) buoy platform was developed for measuring coastal sea levels to provide information where logistical, physical and/or financial constraints prevent the application of established tide gauges and satellite altimetry, and where spatially and temporally discrete tidal data are required to support surveys for monitoring coastal morphodynamics. The buoy

This paper presents an investigation on the symmetric motions and loads of the S-175 containership undergoing severe green water impact that may result in high frequency whipping. Symmetric dynamic response results from two Flexible Fluid Structure Interaction approaches, namely one- and two-way coupling methods are assessed and compared in regular head waves. Numerical computations are performed by

The objective of this work is to investigate the transient flow around a pre-swirl stator pump-jet propulsor. Based on the discussion of the unsteady analysis, we conduct a comparative study on the wake vortices generated by the hybrid RANS/LES family at the design operating condition J=1.0. Due to the interaction between the rotor and stator, the rotor working behind the stator causes the fluctuant

Simulation of a ship's roll motion through equation-based approaches requires restoring moment, added mass moment of inertia and damping coefficients. Accurate estimation of these coefficients enhances the prediction of ship roll response at a resonance condition. However, the magnitude of these coefficients in regular beam seas and close to a resonance condition is unknown. The present study adopts

An eccentricity imperfection may be occurred in the pipes due to the inappropriate manufacturing process. Hence, the dynamic behavior of such geometrically imperfect pipes is extremely required to be explored and compared with the perfect ones. This work investigates the stability and free vibration of fluid-conveying homogenous and functionally graded (FG) pipes with consideration of eccentricity

The selection of the smoothing coefficient of the probabilistic neural network directly affects the performance of the network. Traditionally, all the mode layer neurons use a uniform smoothing coefficient, and then the optimal smoothing parameters suitable for this problem are searched by the optimization algorithm. In this study, the smoothing coefficients of the mode layer neurons connected by the

The arbitrary Lagrange Euler (ALE) finite element method was used to simulate deformation and damage to a cylindrical shell-water-cylindrical shell (CWC) structure subjected to underwater explosion (UNDEX) loading. The experimental and computational results were in agreement, illustrating the validity of the computational scheme in complex fluid-structure interaction problems involving metals subjected

The article focuses on proposing a new hybrid time-Laplace domain response calculation method for symmetrical floating structures by solving Cummins equation, which is depending on the state–space model identified from transfer function. Different from a time or frequency domain method, the proposed approach estimates the state–space model of a floating structure system from the transfer function in

Synthetic fiber ropes are widely used in the maritime industry, with applications from sailboat rigging to offshore platform mooring lines, thanks to their numerous qualities compared to steel cables: light weight, good specific mechanical properties and excellent marine resistance. A key feature of these ropes is their sensitivity to loading history, as this affects subsequent performance. In the

Unsteady turbulent flows in a waterjet propulsion system are investigated at various cruising speeds with the emphasis on pressure fluctuations. The numerical methodology is based on the Reynolds-Averaged Navier-Stokes (RANS) equation with the SST k-ω turbulence model and a sliding mesh technique. The head and efficiency of the waterjet pump are predicted fairly well compared with the available experimental

In this paper, we investigated issues of arctic supply vessel design and fleet composition. Analysis of factors of various nature that influence the performance of the Arctic supply system, as well as exploration the possible ways to improve its efficiency are presented. For addressing this we developed a research approach that joins the holistic parametric design model of arctic supply vessel and

Real-time prediction of ship motion is essential for decision making in shipborne maritime operations. Differences in ship hulls render different ship motion characteristics, which consequently affects the performance of real-time prediction models. In this study, the ship hull scale effects in real-time motion prediction are investigated using the AR model. The ship datasets are generated by applying

This paper presents the development of a numerical optimization tool for the design of a passive U-tube type anti-roll tank (ART) system to mitigate the roll motions of a vessel. A Genetic Algorithm (GA) based optimization scheme has been developed to minimize the objective function, which in the present investigation is chosen to be the area under the roll response transfer function curve. A practical

A silty seabed can be destabilized in two ways under wave loading: by liquefaction or shear failure. In this paper, the wave-induced initial failure mode of a silty seabed under different consolidation conditions is studied using flume experiments. Through a comparison of the pore water pressure, initial failure, and liquefaction development patterns in a relatively soft and dense seabed, it is found

This discussion is based on the paper by Mamouri et al. (2019) (hereafter identified as “the original authors” or “the original paper”). The original authors employed computational fluid dynamics to calculate the flow field around several wind turbine airfoils, and combined this with an evaluation of the entropy generation to estimate the second law efficiency. It came to our attention that the equations

In the uneven flow field, the propeller excitation is transmitted to the hull along with the propulsion shaft system, which is the main exciting force that causes the structural vibration of the ship. A dynamic model to study the transverse vibration of the coupled system of the shaft and submerged conical-cylindrical shell was developed using an analytical method. Flügge equations of motion and beam

This discussion is based on the paper by Cui et al. (2019) (hereafter identified as “the original authors” or “the original paper”). The original authors present a review on the application of CFD in the analysis of self-rectifying turbines for OWC wave energy conversion devices. We feel that this review is incomplete, as it overlooks a number of papers published in recent years that gave a new explanation

The influence of scour on the lateral response of monopile foundations for offshore wind turbines is investigated in this paper. Application of lateral load-displacement (p-y) curves to predict the lateral pile behaviour is subject to uncertainty as many of the presently used design approaches have been derived for long, slender piles. These piles, with typical length/diameter ratios (L/D) of greater

This work is a response to the discussion paper by Ghisu, T. and Cambuli, F. on our recent review paper (Ciu er al., 2019) published in Ocean Engineering. Two main reasons are given for the exclusion of parts of their papers from our review. First, our literature retrieval process was not able to use any published work from after our submission date, nor any work with considerable and inappropriate