Journal of Marine Science and Engineering

Research

25 pages, 7464 KiB

Open AccessArticle

Predicting the Effect of Hull Roughness on Ship Resistance Using a Fully Turbulent Flow Channel

by Roberto Ravenna, Ryan Ingham, Soonseok Song, Clifton Johnston, Tahsin Tezdogan, Mehmet Atlar and Yigit Kemal Demirel

J. Mar. Sci. Eng. 2022, 10(12), 1863; https://doi.org/10.3390/jmse10121863 - 02 Dec 2022

Cited by 1 | Viewed by 2075

Abstract

The consequences of poor hull surface conditions on fuel consumption and emissions are well-known. However, their rationales are yet to be thoroughly understood. The present study investigates the hydrodynamics of fouling control coatings and mimicked biofouling. Novel experimental roughness function data were developed [...] Read more.

The consequences of poor hull surface conditions on fuel consumption and emissions are well-known. However, their rationales are yet to be thoroughly understood. The present study investigates the hydrodynamics of fouling control coatings and mimicked biofouling. Novel experimental roughness function data were developed from the “young” fully turbulent flow channel facility of the University of Strathclyde. Different surfaces, including a novel hard foul-release coating, were tested. Finally, the performance of a benchmark full-scale containership was predicted using Granville’s similarity law scaling calculations. Interestingly, the numerical predictions showed that the novel hard foul-release coating tested had better hydrodynamic performance than the smooth case. A maximum 3.79% decrease in the effective power requirements was observed. Eventually, the results confirmed the practicality of flow channel experiments in combination with numerical-based methods to investigate hull roughness effects on ship resistance and powering. The present study can also serve as a valuable guide for future experimental campaigns using the fully turbulent flow channel facility of the University of Strathclyde. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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32 pages, 34025 KiB

Open AccessArticle

A Fully Coupled CFD-DMB Approach on the Ship Hydroelasticity of a Containership in Extreme Wave Conditions

by Yujia Wei, Atilla Incecik and Tahsin Tezdogan

J. Mar. Sci. Eng. 2022, 10(11), 1778; https://doi.org/10.3390/jmse10111778 - 18 Nov 2022

Cited by 9 | Viewed by 2462

Abstract

In this paper, we present a fully coupled computational fluid dynamic (CFD) and discrete module beam (DMB) method for the numerical prediction of nonlinear hydroelastic responses of a ship advancing in regular and focused wave conditions. A two-way data communication scheme is applied [...] Read more.

In this paper, we present a fully coupled computational fluid dynamic (CFD) and discrete module beam (DMB) method for the numerical prediction of nonlinear hydroelastic responses of a ship advancing in regular and focused wave conditions. A two-way data communication scheme is applied between two solvers, whereby the external fluid pressure exported from the CFD simulation is used to derive the structural responses in the DMB solver, and the structural deformations are fed back into the CFD solver to deform the mesh. We first conduct a series of verification and validation studies by using the present CFD–DMB method to investigate the global ship motion, vertical bending moments (VBMs), and green water phenomenon of the ship in different regular wave conditions. The numerical results agreed favourably with the CFD–FEA model and experimental measurements. Then, the extreme ship motions are studied in focused wave conditions to represent extreme sea conditions that a ship may experience in a real sea state. According to the conclusion drawn from the numerical simulations, it is founded that the focused wave case will lead to the increase of the longitudinal responses of the hull compared to regular wave condition, i.e., the heave, pitch, and total VBMs rise about

25 %

,

20 %

and

9 %

, respectively. In focused wave conditions, intensive ship responses and severe waves cause stronger slamming phenomena. It is found that the instantaneous impact pressure from the focused wave is higher and sharper compared to the regular waves and comes along with the obvious green-water-on-deck phenomena. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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Graphical abstract

29 pages, 12117 KiB

Open AccessArticle

CFD-FEM Simulation of Slamming Loads on Wedge Structure with Stiffeners Considering Hydroelasticity Effects

by Zhenwei Chen, Jialong Jiao, Qiang Wang and Shan Wang

J. Mar. Sci. Eng. 2022, 10(11), 1591; https://doi.org/10.3390/jmse10111591 - 27 Oct 2022

Cited by 4 | Viewed by 1788

Abstract

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 [...] Read more.

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 external fluid pressure exported from the CFD simulation is used to derive the structural responses in the FEM solver, and the structural deformations are fed back into the CFD solver to deform the mesh. Moreover, a tank experiment using a steel wedge model that has the same structural properties is also conducted to compare with the numerical results. Verification and validation of the numerical results indicate that the CFD-FEM coupled method is feasible and reliable. The slamming response results by numerical simulation and experiments, including displacement, velocity, acceleration, slamming pressure, deformation, structural stresses and total forces on the wedge, accounting for hydroelasticity effects in different free falling height conditions are comprehensively analyzed and discussed. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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28 pages, 12744 KiB

Open AccessArticle

Prediction of the Hydrodynamic Forces for a Ship Oscillating in Calm Water by an Improved Higher Order Rankine Panel Method

by Chun-Hsien Wu and Ming-Chung Fang

J. Mar. Sci. Eng. 2022, 10(10), 1337; https://doi.org/10.3390/jmse10101337 - 21 Sep 2022

Cited by 1 | Viewed by 1491

Abstract

This paper presents a frequency-domain Rankine source method based on a biquadratic B-spline scheme with an improved radiation mechanism. The improved radiation mechanism, based on the introduction of spatially varying Rayleigh artificial damping in addition to the simplified Seto’s radiation boundary conditions, is [...] Read more.

This paper presents a frequency-domain Rankine source method based on a biquadratic B-spline scheme with an improved radiation mechanism. The improved radiation mechanism, based on the introduction of spatially varying Rayleigh artificial damping in addition to the simplified Seto’s radiation boundary conditions, is considered for modeling radiation of generated waves at various

τ

conditions, where

τ = ω U / g

including the undercritical condition (

τ < 0.25

); this condition is present when a ship undergoes slow translation or low oscillatory frequency. In evaluations, the proposed method yields accurate solutions for unsteady flows produced by an oscillating, translationally moving submerged singularity. The radiation problem induced by a RIOS bulker is solved to have the resultant added mass and damping coefficients for further comparisons with the experimental data and the public numerical prediction by a simplified combined method at a wide

τ

region. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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31 pages, 10620 KiB

Open AccessArticle

Dynamic of Tunneled Planing Hulls in Waves

by Fatemeh Roshan, Sasan Tavakoli, Simone Mancini and Abbas Dashtimanesh

J. Mar. Sci. Eng. 2022, 10(8), 1038; https://doi.org/10.3390/jmse10081038 - 28 Jul 2022

Cited by 2 | Viewed by 1658

Abstract

A tunneled planing craft is a high-speed boat with two tunnels over the hull bottom that are designed to improve the vessel’s performance. Hydrodynamic performance of tunneled planing hulls in calm-water is well-known, however, current information on wave conditions is limited. In this [...] Read more.

A tunneled planing craft is a high-speed boat with two tunnels over the hull bottom that are designed to improve the vessel’s performance. Hydrodynamic performance of tunneled planing hulls in calm-water is well-known, however, current information on wave conditions is limited. In this study, two different tunneled planing hulls with two degrees of freedom in heave and pitch motions are studied in regular waves by using the computational fluid dynamics (CFD) method based on the Unsteady Reynolds Averaged Navier-Stokes Equations (URANSE) in conjunction with k−ϵ turbulence model. The results demonstrate that tunneled planing hull motions in waves are nonlinear. In addition, it is found that the dynamic responses of heave and pitch motions as well as occurrence portability of the fly-over phenomenon significantly increases as the Froude number grows. Fly-over motions resulted in vertical motions and acceleration up to 5g, high impact pressure, and large induced drag. At a very high planing speed, after flying over the water surface, when the vessel re-enters the water, the resulting hydrodynamic load leads to a second fly-over motion. Since the fly-over is an unwanted movement with adverse effects, these results can provide a better understanding of the fly-over motion that one may consider in future design for improving the planing hull performance. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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19 pages, 5585 KiB

Open AccessArticle

A Numerical Analysis of Dynamic Slosh Dampening Utilising Perforated Partitions in Partially-Filled Rectangular Tanks

by Mitchell G. Borg, Claire DeMarco Muscat-Fenech, Tahsin Tezdogan, Tonio Sant, Simon Mizzi and Yigit Kemal Demirel

J. Mar. Sci. Eng. 2022, 10(2), 254; https://doi.org/10.3390/jmse10020254 - 13 Feb 2022

Cited by 4 | Viewed by 2110

Abstract

Conventional liquefied natural gas (LNG) cargo vessels are imposed with tank-fill limitations as precautions to prevent structural damage and stability-loss due to high-impact sloshing, enforcing cargo volume-fills to be lower than 10% or higher than 70% of the tank height. The restrictions, however, [...] Read more.

Conventional liquefied natural gas (LNG) cargo vessels are imposed with tank-fill limitations as precautions to prevent structural damage and stability-loss due to high-impact sloshing, enforcing cargo volume-fills to be lower than 10% or higher than 70% of the tank height. The restrictions, however, limit commercial operations, specifically when handling spot trades and offshore loading/unloading at multiple ports along a shipping route. The study puts forward a computational fluid dynamic (CFD) sloshing analysis of partially-filled chamfered rectangular tanks undergoing sinusoidal oscillatory kinetics with the use of the explicit volume-of-fluid and non-iterative time-advancement schemes. Establishing a 20% to 60% fill-range, the sloshing dynamics were acknowledged within an open-bore, partitioned, and perforated-partitioned tank when oscillating at frequencies of 0.5 Hz and 1 Hz. The overall torque and static pressure induced on the tank walls were investigated. High-impact slamming at the tank roof occurred at 40% and 60% fills, however, the implementation of the partition and perforated-partition barriers successfully reduced the impact due to suppression and dissipation of the wave dynamics. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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20 pages, 4786 KiB

Open AccessArticle

Research on the Water Ridge and Slamming Characteristics of a Semisubmersible Platform under Towing Conditions

by Fali Huo, Changdong Wei, Chenyang Zhu, Zhaojun Yuan and Sheng Xu

J. Mar. Sci. Eng. 2022, 10(1), 116; https://doi.org/10.3390/jmse10010116 - 15 Jan 2022

Cited by 1 | Viewed by 1545

Abstract

During the towing of semisubmersible platforms, waves impact and superpose in front of the platform to form a ridge shaped “water ridge”, which protrudes near the platform and produces a large slamming pressure. The water ridges occur frequently in the towing conditions of [...] Read more.

During the towing of semisubmersible platforms, waves impact and superpose in front of the platform to form a ridge shaped “water ridge”, which protrudes near the platform and produces a large slamming pressure. The water ridges occur frequently in the towing conditions of semisubmersible platforms. The wave–slamming on the braces and columns of platform is aggravated due to the water ridges, particularly in rough sea conditions. The effect of water ridges is usually ignored in slamming pressure analysis, which is used to check the structural strengths of the braces and columns. In this paper, the characteristics of the water ridge at the braces of a semisubmersible platform are studied by experimental tests and numerical simulations. In addition, the sensitivity of the water ridge to the wave height and period is studied. The numerical simulations are conducted by a Computational Fluid Dynamics (CFD) method, and their accuracy is validated based on experimental tests. The characteristics of the water ridge and slamming pressure on the braces and columns are studied in different wave conditions based on the validated numerical model. It is found that the wave extrusion is the main reason of water ridge. The wave–slamming pressure caused by the water ridge has an approximately linear increase with the wave height and is sensitive to the wave period. With the increase of the wave period, the wave–slamming pressure on the brace and column of the platform increases first and then decreases. The maximum wave–slamming pressure is found when the wave period is 10 s and the slamming pressure reduces rapidly with an increase of wave period. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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26 pages, 12759 KiB

Open AccessArticle

CFD Simulation and Experimental Study on Coupled Motion Response of Ship with Tank in Beam Waves

by Tao He, Dakui Feng, Liwei Liu, Xianzhou Wang and Hua Jiang

J. Mar. Sci. Eng. 2022, 10(1), 113; https://doi.org/10.3390/jmse10010113 - 14 Jan 2022

Cited by 11 | Viewed by 2232

Abstract

Tank sloshing is widely present in many engineering fields, especially in the field of marine. Due to the trend of large-scale liquid cargo ships, it is of great significance to study the coupled motion response of ships with tanks in beam waves. In [...] Read more.

Tank sloshing is widely present in many engineering fields, especially in the field of marine. Due to the trend of large-scale liquid cargo ships, it is of great significance to study the coupled motion response of ships with tanks in beam waves. In this study, the CFD (Computational Fluid Dynamics) method and experiments are used to study the response of a ship with/without a tank in beam waves. All the computations are performed by an in-house CFD solver, which is used to solve RANS (Reynold Average Navier-Stokes) equations coupled with six degrees-of-freedom solid-body motion equations. The Level Set Method is used to solve the free surface. Verification work on the grid number and time step size has been conducted. The simulation results agree with the experimental results well, which shows that the numerical method is accurate enough. In this paper, several different working conditions are set up, and the effects of the liquid height in the tank, the size of the tank and the wavelength ratio of the incident wave on the ship’s motion are studied. The results show the effect of tank sloshing on the ship’s motion in different working conditions. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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19 pages, 7203 KiB

Open AccessArticle

Study on Slamming Pressure Characteristics of Platform under Freak Wave

by Fali Huo, Hongkun Yang, Zhi Yao, Kang An and Sheng Xu

J. Mar. Sci. Eng. 2021, 9(11), 1266; https://doi.org/10.3390/jmse9111266 - 13 Nov 2021

Cited by 7 | Viewed by 2167

Abstract

Freak waves have great peak energy, short duration, great contingency, and strong nonlinear characteristics, and can cause severe damage to ships and marine structures. In this study, numerical simulations in conjunction with experimental tests are applied to study air gap response and wave [...] Read more.

Freak waves have great peak energy, short duration, great contingency, and strong nonlinear characteristics, and can cause severe damage to ships and marine structures. In this study, numerical simulations in conjunction with experimental tests are applied to study air gap response and wave slamming loads of a semi-submersible offshore platform under a freak wave. A three-dimensional wave tank, which is created based on the computational fluid dynamics (CFD) method, is applied to study the hydrodynamic responses of a semi-submersible platform. The numerical model of the tank and offshore platform system are checked according to the experimental results. A typical freak wave is modelled in numerical wave tanks by the linear superposition method, and its significant wave height is 13.03 m. It is found that the freak wave is closely associated with the wave slamming. The appearance of the freak wave gives rise to a negative air, gap which appears on the side of the back wave surface at the bottom of the deck box, and considerable slamming pressure is generated. Furthermore, the wave run up at the junction of the column and the buoyancy tank is also seen due to the freak wave. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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23 pages, 6814 KiB

Open AccessArticle

CFD Prediction of Ship Seakeeping and Slamming Behaviors of a Trimaran in Oblique Regular Waves

by Xiyu Liao, Zhanyang Chen, Hongbin Gui and Mengchao Du

J. Mar. Sci. Eng. 2021, 9(10), 1151; https://doi.org/10.3390/jmse9101151 - 19 Oct 2021

Cited by 12 | Viewed by 2125

Abstract

The main hull encounters waves at first and causes waves to break, when trimarans are subject to the slamming in head waves. At this moment, emergence phenomena of side hulls will not occur. Thus, the slamming study of trimarans in oblique waves presents [...] Read more.

The main hull encounters waves at first and causes waves to break, when trimarans are subject to the slamming in head waves. At this moment, emergence phenomena of side hulls will not occur. Thus, the slamming study of trimarans in oblique waves presents further practical significance. In this study, a CFD method is used for trimaran seakeeping and slamming analysis. An overset grid technique is adopted to simulate ship motions in waves. Firstly, to further verify the present method, a series of verification and validation studies is conducted. Then, the motion responses and slamming pressure with different control parameters, such as forward speed and ship heading angle, are calculated and discussed. The comparative results indicate that the seakeeping and slamming behaviors of trimarans differ significantly from those of conventional monohull ships. Finally, severe bow slamming and green water in oblique waves are also observed and investigated, which should be given enough attention during ship design and evaluation. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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14 pages, 5188 KiB

Open AccessArticle

Dynamic Response Analysis of a Bulk Carrier by Nonlinear Hydroelastic Method

by Zhanyang Chen, Hongbin Gui, Xiyu Liao and Mengchao Du

J. Mar. Sci. Eng. 2021, 9(8), 877; https://doi.org/10.3390/jmse9080877 - 13 Aug 2021

Cited by 1 | Viewed by 1847

Abstract

With increasing demands for huge ship dimensions and the wide use of high-strength steel, the influence of slamming and elastic structure on structural strength cannot be ignored. Therefore, in this paper, a three-dimensional (3D) nonlinear hydroelastic theory is introduced, in which the nonlinear [...] Read more.

With increasing demands for huge ship dimensions and the wide use of high-strength steel, the influence of slamming and elastic structure on structural strength cannot be ignored. Therefore, in this paper, a three-dimensional (3D) nonlinear hydroelastic theory is introduced, in which the nonlinear hydrostatic restoring force caused by instantaneous wetted surface as well as slamming force are taken into consideration, and the bending moments with/without slamming effects are calculated, respectively. Numerical simulations of the dynamic response of a flexible hull at different speeds are carried out using the finite element analysis software MSC/PATRAN. By comparison with the results of classical beam theory, the accuracy of the dynamic analysis method is studied. Finally, the dynamic response method is compared with the quasi-static method and classical beam theory. By analyzing and quantifying the influence of forward speed and nonlinear factors on structural responses, the reasonable applicable conditions for different methods are discussed, which can be used as reference in the structure design of bulk carriers. Full article

(This article belongs to the Special Issue Ship Motions and Wave Loads)

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