Shan Wang

• Ph.D
• Professor (Assistant) at University of Lisbon

Under complex hydrodynamic conditions, Unmanned Surface Vessel (USV) exhibits non-stationary and nonlinear dynamic behaviors. Extreme short-term prediction of such nonlinear motion is therefore critical for ensuring navigational safety. To improve the prediction accuracy, a VMD-CNN-LSTM combined prediction model was applied based on Variational Mod...

The long-term responses of offshore wind turbines (OWTs) are critical in the design phase, where precise assessments ensure structural reliability and operational efficiency. The environmental contour method (ECM) enables efficient analysis of design responses by focusing on a selected set of critical environmental conditions that predominantly dri...

This study explores the hydrodynamic behaviour of a fish cage in a steady current by employing a fluid–structure interaction model with one-way coupling between a fluid solver and a structural model. The fluid field around the fish cage is predicted using a computational fluid dynamics solver, while the stress and deformation of the netting are cal...

To investigate the influencing factors on the operation of an offshore wind turbine installation ship, a neural network, as a machine-learning method, is built to predict and analyze the motion response of a floating derrick in the process of a lifting operation under an external environmental load. The numerical method for the double floating body...

The behavior of a chemical tanker (CT) in extreme waves was discussed in detail, that is, in terms of rigid body heave and pitch motions, vertical bending moments (VBMs) amidships, green water, and slamming impacts through the analysis of the experimental data from model tests. Regular wave tests conducted for two wave steepness showed that the inc...

Enhancing the precision of short-term mooring tension prediction holds the key to bolstering safety measures within marine operations. In this study, a hybrid model which takes the advantages of convolutional neural networks (CNN) and gated recurrent units (GRU) is developed to predict dynamic mooring tension time series of a wave energy converter....

This study investigates scale effects on hydrodynamics of a 2D submerged circular cylinder subjected to incoming flow in Computational Fluid Dynamics simulation. The primary focus is the influence of varying scale ratios on drag coefficient, lift coefficient, and vortex shedding frequency in high Reynolds number conditions. The methodology involves...

The study investigates the behaviour of a liquified natural gas carrier in regular head waves using the Smoothed Particle Hydrodynamics meshfree method implemented in DualSPHysics. A numerical wave tank in three-dimensional domain is generated using the modified Dynamic Boundary Conditions and compared with the theoretic wave surface using Stokes e...

In this work, the hydrodynamics forces on semi-submerged and submerged cylinders under a steady flow are analysed using the numerical code DualSPHysics, which implements the Smoothed Particle Hydrodynamics (SPH) method. The published experimental tests which were conducted in the Shanghai Ship and Shipping Research Institute, for submerged and semi...

Results are presented of a benchmark study organised by the Marstruct Virtual Institute on motion and global wave loads on a warship model in regular waves. The aim of the study is the quantification of the uncertainty in numerical whipping predictions. Nine institutions participated in the benchmark with 6 codes, quantifying the hydroelastic respo...

The influence of mooring systems with lines of different material on the dynamic response of a floating wind turbine is studied using a 5 MW OC4-DeepCwind semi-submersible wind turbine as a representative prototype in this study. Two types of mooring systems were designed using the MoorDyn module in OpenFAST software (v3.1.0): one uses chains, and...

This paper investigates the vertical bending, horizontal bending, and torsion loads on an ultra-large container ship in high sea states and different Froude numbers using a strip theory-based 2D time domain code. The numerical solver is based on a potential flow theory and a body nonlinear approach. The hydrody-namic coefficients are estimated usin...

A new uncertainty quantifier is presented for linear transfer functions of wave-induced ship motions and loads obtained by various seakeeping codes. The numerical simulations are conducted for the high-speed Flokstra container ship in regular waves at various heading angles, and the results are compared with existing experimental data. The study em...

This paper reviews the importance of uncertainties in hull girder loads influenced by flexible fluid structure interactions. The focus is on developments in the field of hydroelastic modelling, simulation and model tests of practical relevance to the prediction hull girder wave load predictions and their validation. It is concluded that whereas hyd...

This paper presents a comprehensive experimental study on the effect of extreme waves on a LNG carrier. The LNG carrier model was equipped with a variety of sensors to measure motions, green water height on deck as well as local and global loads. Experiments in transient wave packets provided the general performance in waves in terms of response am...

The objective of the paper is to identify slamming characteristics of ships in abnormal waves by analyzing the experimental slamming loads for an LNG carrier from the model tests of the ship, which were conducted at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70. To validate the experiments, the numerical...

In this paper, both numerical and experimental methods are adopted to study the fluid-structure interaction (FSI) problem of a wedge structure with stiffeners impacted with water during the free-falling water entry process. In the numerical model, a partitioned two-way couple of CFD and FEM solvers is applied to deal with the FSI problem, where the...

This study addresses the planning procedures for the installation of the mooring systems that support the floating offshore wind turbines in a wind farm. It considers the logistics of the installation process and discusses the important role of the weather windows in the planning of those operations at a preliminary stage of the project. The case s...

Committee Mandate Concern for the dynamic response of ship and offshore structures as required for safety and serviceability assessments, including habitability. This should include steady state, transient and random responses. Attention shall be given to dynamic responses resulting from environmental, machinery and propeller excitation. Uncertaint...

Discussion Discussers’ reports and floor discussions, including the replies by the committees, are included in this Volume 3 discussion paper. Committee Mandate Concern for the dynamic response of ship and offshore structures as required for safety and serviceability assessments, including habitability. This should include steady state, transient...

Analytical solutions to study the elastic dynamic responses of a flat composite plate are developed based on the orthotropic thin plate theory and modal analysis. The spatial uniform slamming pressure is simplified to two types of time-dependent impact loads, i.e. an exponentially decaying impulse and a triangle impulses, which are characterized by...

Results are presented of a benchmark study organised by the ISSC-ITTC Joint Committee on global linear wave loads on a container ship with forward speed. The aim of the study is the assessment of the uncertainty in linear transfer functions due to different seakeeping codes and consequences on long-term extreme vertical wave bending moments. Seven...

Numerical simulations are increasing their importance as an alternative to physical tests in the field of hydrodynamics. To ensure the accuracy of numerical results, quantification of associated uncertainties is crucial. In this paper, comparisons are made between the uncertainty quantification methods and the accuracy of mesh-free and mesh-based s...

The objective of the paper is to identify slamming characteristics of ships in abnormal waves by analysing the experimental slamming loads for an LNG carrier from the model tests of the ship, which were conducted at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70. To validate the experiments, the numerical...

The present work aims at assessing the random experimental uncertainties in the response behaviour of an LNG carrier on the model tests that were carried out at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70 within the EU project EXTREME SEAS. The response metrics of interest include the heave and pitch m...

This work studies the effects of the dynamic axial stiffness of elastic moorings on the dynamic behaviour of a point absorber wave energy converter. Following two mooring analysis procedures, coupled dynamic analysis of a taut-moored WEC with three legs is performed using the FEM program DeepC in three irregular wave conditions. Two synthetic fibre...

Three-dimensional effects on slamming loads predictions of a ship section are investigated numerically using the unsteady incompressible Reynolds-averaged Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in interDyMFoam solver in open-source library OpenFoam. A convergence and uncertainty study is performed con...

The mooring force in a fish cage array subjected to currents and waves is investigated using the finite element method. Firstly, the numerical model of a fish cage array with six gravity cages is built by Ansys/APDL. Collars and bottom rings are simulated with pipe and beam elements while the rest structure is simulated with link elements, includin...

A hydrodynamic study on the asymmetrical water impact of two-dimensional wedges with roll angle is presented. The slam induced loads on the wedges entering calm water with both vertical and horizontal velocities are predicted based on the explicit finite element method. The effects of the horizontal impact velocity and the roll angle are investigat...

The two-dimensional water entry of bow-flared sections is studied by using a Multi-Material Arbitrary Lagrangian- Eulerian (MMALE) formulation and a penalty-coupling algorithm. A convergence study is carried out, considering the effects of mesh size, the dimension of fluids domain, and fluid leakage phenomenon through the structure. The predicted r...

The two-dimensional hydrodynamic problem of a symmetric wedge vertically impacting in calm water is analysed by using an explicit finite element method based on a multi-material Eulerian formulation. The slam-induced loads on wedges with different deadrise angle at a constant velocity are calculated, including pressure distribution, maximum pressur...

This paper presents a co-simulation method for numerical prediction of nonlinear hydroelastic response of ship advancing in severe wave conditions. Two-way coupling of CFD and FEA solvers is applied where the external fluid pressure exported from the CFD simulation is used to derive the structural responses in the FEA solver and the structural defo...

The open source Computational Fluid Dynamics (CFD) library, OpenFOAM, is utilized to simulate the water impact of two-dimensional wedges and ship bow sections. For the free falling cases, the predicted results are validated against existing experimental data, and the parameter study is performed regarding the number of cells, time step, and width o...

Numerical uncertainty due to discretization on the Arbitrary Lagrangian-Eulerian (ALE) Finite Element method is investigated in the study. The paper quantifies uncertainty using two ITTC recommended methods, and also applies a constant Courant-Friedrichs-Lewy (CFL) number based discretization approach, instead of performing the independent grid and...

The objective of this work is to develop an efficient method to carry out the preliminary design of the mooring system for a wave energy converter. A practical mooring design procedure is applied to a specific case of study, and it can be replicated for other cases. Firstly, the static analysis is performed for a configuration with three mooring ca...

Three-dimensional effects on slamming loads predictions of a ship section are investigated numerically using the unsteady incompressible Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in interDyMFoam solver in open-source library OpenFoam. A convergence and uncertainty study is performed cons...

Water entry of a rigid hemisphere is simulated using the unsteady incompressible Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in the open-source library OpenFoam. The solver InterDyMFoam is applied and the algorithm PIMPLE which is a combination of PISO (Pressure Implicit with Splitting of...

Sloshing is a highly nonlinear movement that can lead to dynamic loads on tanks. These loads can affect, for example, Liquefied Natural Gas (LNG) vessels by modifying the movement of ships on waves. This is a key point in the design of anti-roll tanks used to damp the roll movement of ships. The coupling effect between sloshing and motions of ship...

This presentation reviews the importance of identifying uncertainties in modelling and validation of ship wave loads influenced by flexible fluid structure interactions (FFSI). We outline recent developments in the field of hydroelastic modelling, simulation and model testing developments with focus on specific examples of practical relevance (e.g....

The performance of the three hybrid mooring systems was studied by conducting 1:40 model tests of a moored point absorber subjected to regular and irregular waves. The compact hybrid mooring adopts two segments design, i.e., a top synthetic fibre rope (polyester or nylon) and a bottom chain. A submerged buoy is installed on the joint between these...

Model tests are conducted to study nonlinear mechanical characteristics of nylon, polyester and high modulus polyethylene. Static tensile and cyclic loading tests are carried out to study the static and dynamic stiffness respectively. Cyclic loading tests with different mean loads and load amplitudes are designed to study the influence of these two...

The present work investigates the influence of mooring material on the hydrodynamic responses of a point absorber by experimental tests. Three taut mooring systems are considered with different materials, namely wire, nylon and polyester. In order to study the influence of mooring material on point absorber hydrodynamic responses, the other factors t...

Three-dimensional effects on slamming loads predictions are investigated numerically using the unsteady incompressible Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in the open-source library OpenFoam. Three cases of free-falling water entry problems are considered. The numerical solutions a...

Fluid structure interactions (FSI) as, for example, slamming on ships and WECs, are one of the most interesting applications of the CFD methods due to their capability to simulate any scenario and to provide practical physical quantities that could be difficult to obtain in scaled models or prototypes. Therefore, the improvement of the numerical co...

The paper evaluates the response of an aluminium stiffened panel of a fast displacement craft under bow flare slamming loads by using three finite element methods: (1) a linear static analysis to calculate the structural elastic deformation and stress under the design load; (2) an independent analysis of the slamming load and the elastic structural...

Tensile test experiments are performed to study the nonlinear behavior of a nylon mooring rope at different scales. A nylon rope, consisting of 8-strands braided, is considered in the experiments at three different scales (a strand, a sub-rope, and the full rope). The load-elongation relationships of the rope subjected to cyclic loading with variou...

A series of 1:50 model tests are conducted to study the motion responses and energy harvesting performance of a novel dual chamber floating oscillating water column device moored by three flexible mooring systems in regular and irregular waves. This novel energy conversion device consists of one traditional oscillating water column chamber and one...

The effects of fluid compressibility on the motions and hydrodynamic forces of a free-falling wedge are investigated using the Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method which are implemented in the open-source library OpenFoam. The initial slamming, transition, collapse and post-closure stages during the water...

A compact mooring system concept is proposed. This novel mooring is composed of submerged buoy and three segments of nylon ropes, which is suitable for the large wave energy converters and wave energy converter array due to its high flexibility and small mooring radius. The performance of this mooring concept was studied experimentally when it was...

This study presents a comprehensive experimental assessment of three hybrid mooring systems for a heaving-buoy wave energy converter. Free decay model tests are conducted to study the natural periods in heave, pitch and surge modes of the buoy when it is moored with different mooring configurations. A series of regular and irregular wave model test...

A 3D water entry of a typical bow model of River-to-Sea ship is studied experimentally. A large number of systematic experiments have been performed for the bow model with different pitch angles. Considering various pitch angles and impact velocities in the model tests, the slamming pressure distributions on the bottom of the bow are presented and...

The whole dropping process of a horizontal cylinder from the water surface is investigated through OpenFOAM based CFD method. A good agreement between the simulations and experimental results for a negatively buoyant (relative cylinder to water mass density, ρ'>1) falling horizontal cylinder with initial water entry velocity, Vs = 0.5 m/s, demonstr...

A review of some representative floating wave energy converter (WEC) projects in the world, including the wave energy capturing technology, development history, main dimensions and tested sea sites is presented. The design essentials of WEC mooring system are discussed and a mooring system design procedure for WEC is proposed, which includes the int...

A time domain modelling method coupled with a finite element cable model is used for the study of a buoy moored with two different configurations: catenary and taut mooring systems. The highly dynamic wave energy converters in shallow water usually require coupling dynamic analysis between the floating body and the mooring system to accurately pred...

An overview on synthetic mooring cables for marine applications is presented. The use of synthetic fibre ropes in mooring lines for marine applications is becoming more common due to the lower submerged mass per unit length, a lower cost per unit length and the potential to reduce peak loadings. A clear characterization of nonlinear mechanical beha...

To investigate the slamming pressure on the bottom of a wet-deck structure of a multihull vessel, the water impact problem of a stiffened steel panel is simulated by using a fully coupled ALE/FEM algorithm which is implemented in the commercial software LS-DYNA. The Lagrangian formulation is used to describe plane-strain deformations of the hull pa...

The bottom slamming of a chemical tanker and a LNG carrier advancing in irregular waves is investigated numerically and compared with experiments. The probability of slamming occurrence on longitudinal locations and the slamming induced pressures on the bottom of two ships are discussed. It is considered that slamming occurrence at a point is depen...

Model tests have been conducted to study the performance of alternative mooring sys-tems aimed to be used at a later stage in a wave energy converter under development. The initial set of tests are intended to establish the properties of single lines of different configuration and thus a simple buoy has been chosen as the floater. Two mooring syste...

To investigate the slamming pressure on the bottom of a wet-deck structure of a multihull vessel, the water impact problem of a stiffened steel panel is simulated by using a fully coupled ALE/FEM algorithm which is implemented in the commercial software LS-DYNA. The Lagrangian formulation is used to describe plane-strain deformations of the hull pa...

The R&D project OPWEC—Optimizing Wave Energy Converters intends to develop, optimize and technically evaluate two different technologies to harness wave energy, using a composite modelling approach that combines physical and numerical models. The paper describes the main objectives of the project and the most significant features of one of the conc...

A simplified method is proposed to model the water impact of an elastic wedge, by combining a modal analysis for the structural deflection and an analytical model for the hydrodynamic pressure on a rigid body. The structural deflections are expressed by wet modes shapes of the beam, and are calculated using modal superposition and Duhamel integral...

A hydroelastic analysis of a rectangular plate subjected to slamming loads is presented. An analytical model based on Wagner theory is used for calculations of transient slamming load on the ship plate. A thin isotropic plate theory is considered for determining the vibration of a rectangular plate excited by an external slamming force. The forced...

The paper presents an overview of studies of slamming on ship structures. This work focuses on the hull slamming, which is one of the most important types of slamming problems to be considered in the ship design process and the assessment of the ship safety. There are three main research aspects related to the hull slamming phenomenon, a) where and...

Hydroelastic water impacts of panels with different deadrise angles (10º and 30º,), entry velocities (1m/s, 3m/s, 6m/s and 8m/s), plate thicknesses (5 mm, 8 mm and 11 mm), and edge boundary conditions are simulated by using the finite element method. To quantify the hydroelastic effects, the results of the slamming loads and maximum deflections fro...

The objective of the present work is to investigate the dynamic structural response of perforated plates subjected to water impact load. A fully coupled ALE/FEM method, is used to simulate the fluid–structure coupling problem. The deformations of the plate and of the water are coupled through the hydrodynamic pressure subjected by the water on the...

A simplified method, which combines the Euler–Bernoulli beam theory for structural vibration and Wagner’s theory for hydrodynamic loading, is presented to study the hydroelastic vibration of bottom plating subjected to wave impact. The simplified method is based on the assumption that the structural deformation does not affect the loading on the we...

This paper presents calculations of ship motions, slamming occurrence probability and slamming loads on the bow of a ship hull in irregular waves. The results are compared with the experimental data from model tests of a 170 m chemical tanker with Fn=0 in head seas. Ship motions are calculated by using a partially nonlinear time domain code based o...

The probability of slamming occurrence of a chemical tanker subjected to irregular waves is studied numerically and experimentally. It is considered that slamming occurrence is dependent upon two conditions: the relative vertical motion at the same longitudinal position of the ship being larger than the vertical distance from the still water to the...

The objective of the present study is to analyze the effect of longitudinal compressive force on hydroelastic responses of a horizontal plate impacting with the water surface. The longitudinal bending behavior of a horizontal elastic plate is approximated by the behavior of longitudinal strips represented as an Euler-beam model, and the hydrodynami...

The two-dimensional water entry of bow-flared sections is studied by using a Multi-Material Arbitrary Lagrangian-Eulerian (MMALE) formulation and a penalty-coupling algorithm. A convergence study is carried out, considering the effects of mesh size, the dimension of fluids domain, and fluid leakage phenomenon through the structure. The predicted re...

A hydrodynamic study on the asymmetrical water impact of two-dimensional wedges with roll angle is presented. The slam induced loads on the wedges entering calm water with both vertical and horizontal velocities are predicted based on the explicit finite element method. The effects of the horizontal impact velocity and the roll angle are investigat...