ISP Journal issues

ISP logoOn this page, you will find short summaries of the articles included in the relevant editions of ISP Journal, per year and quarterly edition.
With each article you will find a link to the IOS press website, where you can read more about that article and the relevant edition and how to order.

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ISP Volume 66, nr 3

ISP Volume 66, issue 3 of 2019, contains articles on slamming loads on wave piercing catamarans, on the relation between seabed stiffness and fatigue life of catenary risers under wave loads, and on continuous hull monitoring by E-inspection.  Summaries, as well as the full articles can be found on https://content.iospress.com/journals/international-shipbuilding-progress/66/3


Wet-deck slamming loads and pressures acting on wave piercing catamarans

Authors:  B. Shabani, J. Lavroff, D.S. Holloway, M.R. Davis and G.A. Thomas

Abstract
Wet deck slamming, wave piercing catamaransThe wet-deck height and centre bow configuration in wave piercing catamarans are critical design factors which influence slamming occurrence and severity.
In this paper, the wet-deck slamming loads and pressures acting on a 112 m catamaran with a centre bow were investigated in regular waves in two wave heights.
A 2.5 m hydroelastic model with three alternate configurations of wet-deck vertical clearance was tested at a speed of 2.89 m/s (38 knots full-scale equivalent).
The results showed that at the instant of slamming the centre bow immersion depth relative to the undisturbed incident wave elevation was less than two thirds of the maximum immersion depth during the wet-deck slam event.
The location of maximum slamming pressure was found to be in the range between 77% and 80% of the overall length from the transom.
The relationship between the relative velocity at impact and slamming force indicated that slamming loads in the order of the vessel weight can occur for the parent design when the relative velocity at slam is about a quarter of the forward speed.
Overall, increasing the wet-deck height was more beneficial for reduction of slamming loads and pressures in smaller waves than in large waves.


Effect of seabed stiffness on fatigue life of steel catenary risers due to random waves

Authors: A. Taheri and M. Alizadeh

Abstract

Today’s oil and gas industry is facing deeper waters and harsher environmental conditions. Offshore platforms and marine risers, as the main parts of this industry, have many challenges and design issues. Steel Catenary Riser (SCR) connected to Floating, Production, Storage, and Offloading unit (FPSO), is a preferred and commonly used solution to the challenges. It is needed to have more understandings of SCR behavior. So in this study, the significance of SCR-seabed interaction is investigated. Also, the effect of seabed stiffness on the structural behavior of the SCR is studied. Results show that the seabed stiffness makes considerable differences in dynamic and fatigue responses of SCRs in the touch down zone (TDZ) and reveal the importance of proper seabed stiffness modeling. Model (I), which represents weak soils with very low stiffness, could resist on continuously applied harsh environmental condition for 139.6 days. Model (IV) which represents a very stiff seabed, had a minimum fatigue life of about 6.5 percent of the model (I). The results indicated that the SCR responses were highly separated in terms of fatigue performance especially for weak to normal soils.


E-inspection: effect of continuous hull monitoring on ship safety and crew workload

Authors: P. Antão, M. Hoogeland, A.W. Vredeveldt and F.P. Santos

Abstract

Crewmembers are exposed to high work pressure. Pressure on freight tariffs motivates cost reduction in manning and maintenance, whilst societal developments show decreasing tolerances towards incidents. In conjunction with the developments towards autonomous shipping, the need for continuous and unmanned inspection increases. Considerable progress had been made with respect to monitoring machinery condition, however, the hull structure is as relevant for inspection and maintenance. This will require enhanced inspection, i.e., E-inspection. For hull structure corrosion and fatigue are of main interest. The applica- tion of E-inspection, directs the work effort from the crew to the location of interest, at the right time. It gives also the option to monitor the health status of a ship from shore. This paper summarizes the E- inspection methods and how they will help the crew reducing inspection workload.


ISP Volume 66, nr 2

ISP Volume 66, issue 2 of 2019, contains articles on ship added resistance in waves, optimization of thruster locations on offshore vessels, application of plastics for non-structural components of marine engines as well as an article on distributed energy resources in cruise ships. 

More extensive summaries, as well as the full articles can be found on https://content.iospress.com/journals/international-shipbuilding-progress/66/2

Experimental assessment of effects of bow-wave breaking on added resistance for the fast ship

Authors: B. Choi, P.R. Wellens and R.H.M. Huijsmans

Abstract

The linear relationship between the pressure and the relative wave elevation on the hull surface is a prominent factor to be reconsidered in relation to the uncertainty of the added resistance. An evaluation method is proposed to access the nonlinear relationship between the hull pressure and the relative wave elevation, which has a decisive influence on the added resistance evaluation. This method is used to experimentally investigate the effect of bow-wave breaking of the fast displacement ship in waves. The results show that the nonlinearity between relative wave elevation and hull surface pressure due to the plunging breaking of a bow wave is intuitively detected using the proposed analytical tool. This study provides important insight into the nonlinear relationship between relative wave elevation and added resistance. In addition, the findings provide a better understanding of the process of plunging breaking of bow waves.

 

This publication is available at IOS Press through this link



Optimal thruster location on offshore DP vessels

Authors: F. Mauro and P. Nabergoj

Abstract

ISP66-2 Mauro e.a.During a design- or conversion process of an offshore vessel, the DP system is usually not one of the primary constraints for the general arrangement of the vessel. Usually the location of the thrusters is driven by the available internal spaces, i.e. the thruster positions are not optimized to the maximum capability. Therefore, it is considered worthwhile to study in more detail thruster arrangements aimed to maximize the capability of the vessel to keep position with a certain amount of installed power. In the present work a procedure aimed to find optimal thruster locations on the hull during the early design stage is presented. Using a quasi-static approach for DP capability evaluation, an optimization procedure based on a genetic algorithm has been developed, considering the constraints given by the vessel geometry. The method is applied to a test case, being a typical offshore vessel, where the original layout is compared with two possible optimized configurations.

This publication is available at IOS Press through this link


Design of non-structural components for marine engines based on nano-engineered thermoplastic polymers

Authors: S. Bertagna, E. Laurini, A. Mannò, C. Nasso, S. Pricl and V. Bucci

Abstract
ISP66-2 Bertagna e.a.During a design- or conversion process of an offshore vessel, the DP system is usually not one of the primary constraints for the general arrangement of the vessel. Usually the location of the thrusters is driven by the available internal spaces, i.e. the thruster positions are not optimized to the maximum capability. Therefore, it is considered worthwhile to study in more detail thruster arrangements aimed to maximize the capability of the vessel to keep position with a certain amount of installed power. In the present work a procedure aimed to find optimal thruster locations on the hull during the early design stage is presented. Using a quasi-static approach for DP capability evaluation, an optimization procedure based on a genetic algorithm has been developed, considering the constraints given by the vessel geometry. The method is applied to a test case, being a typical offshore vessel, where the original layout is compared with two possible optimized configurations.

 

 

This publication is available at IOS Press through this link


Shipboard distributed energy resources: Motivations, challenges and possible solutions in the cruise ship arena

Authors: A. Boveri, G.A, Di Mare, D. Rattazzi, P. Gualini, L. Magistri and F. Silvestro

Abstract
ISP66-2 Boveri e.a.Metallic alloys play a leading role in marine engine construction. To reduce cost and weights, there is a constant need for new, high-performance materials for the production of non-structural components of marine engines. Nano-engineered thermo-plastic polymers (NETP’s) are ideal alternatives, allowing for additional benefits (e.g. simplified maintenance and inspection operations). The application of plastic-based materials also contributes to environmental sustainability, both in terms of component production process and recyclability. The use of these materials in marine engine design requires computer multiscale simulations to tailor-fit their molecular structure in order to achieve the expected performances required by specific, advanced functions. For the introduction of non-structural plastic components in marine engines a specific rule framework still has to be defined.  In this paper a certification procedure is proposed and applied to the case of plastic cylinder head cover, starting from the analysis of the rule framework currently used for metallic alloys.

This publication is available at IOS Press through this link


ISP Volume 66, nr 1

ISP Volume 66, issue 1 of 2019, contains 6 articles on various topics.
This is a special issue, containing extended versions of selected papers of the NAV2018 conference held in Trieste, Italy in June 2018. It contains various articles on ship strength, design and construction aspects as well as an article on numerical
investigations of a cavitating propeller.
More extensive summaries, as well as the full articles can be found via this link


Comparative study between analytical and FE analysis for the ultimate strength assessment of pitted platings

Authors: V. Piscopo and A. Scamardella
Abstract:

The ultimate strength assessment of platings affected by pitting corrosion wastage is a basic issue for the scantling and design of ship structures. In the past, several non-linear FE analyses were performed to investigate the incidence of pitting degree and corrosion depth on the ultimate strength of plate panels, with the main aim of providing some approximate formulations, useful at least in the preliminary project phase.
Based on actual state of art, the main aim of current research is to provide an analytical formulation for the ultimate strength assessment of platings with random pitting corrosion wastage, by solving the Marguerre non-linear governing
differential equations for large deflection analysis of platings in the post-buckling
regime. In this respect, a comparative analysis between the analytical solution and a series of FE results is preliminarily performed for uncorroded platings, combining different levels of initial geometrical imperfections and welding residual stresses.
Subsequently, the comparative analysis is extended to platings affected by pitting corrosion wastage. Hence, different levels of pitting and corrosion intensity degrees are properly combined in order to investigate the goodness of the proposed analytical formulation.

This publication is available at IOS Press through this link


Mechanical buckling analysis of explosive welded joints used in shipbuilding

Authors: P. Corigliano, V. Crupi and E. Guglielmino
Abstract:
Aluminum superstructures and steel hull connections are of fundamental importance in ships.This study regards the buckling analysis of explosion welded joints, made of three layers (ASTM A516 low carbon steel, pure aluminium, A5086 aluminium alloy) and used in ship structures. Tensile and compressive tests were carried out on explosion welded specimens. The Infrared Thermography was used to detect the superficial temperature of the specimen during the tensile test and three phases of the temperature evolution were observed. The Digital Image Correlation technique was applied during the tests for the detection of displacement and strain fields. A theoretical analysis, considering the different materials was also performed for the analysis of buckling, which occurred during the compressive tests. Furthermore, a non-linear finite element analysis, considering the different mechanical properties of the explosive welded joint, was performed and was validated by means of the experimental results, obtained by the compressive tests.

This publication is available at IOS Press through this link


Integrated design of an eco-friendly wooden passenger craft for inland navigation

Authors: C. Nasso, U. la Monaca, S. Bertagna, L. Braidotti, F. Mauro, G. Trincas, A. Marinó and V. Bucci
Abstract:

The continuous increasing attention to environmental sustainability and air pollution reduction for transport systems, requires not only to adopt new technologies and innovative solutions to limit vehicles emissions, but also to study their life-cycle. In case of inland navigation, the operation close to urban areas or in natural protected environments requires the adoption of a green propulsion. Moreover, especially for small crafts, the problem of ship disposal at the end of life is of high importance, even once plastic materials should be disposed, due to high costs and process complexities. For such a reason the design of a new generation green passenger craft requires the analysis and knowledge of multiple engineering fields, that could lead to a fast and successful design only by means of an integrated approach. In the present work, this approach will be applied to the design of a passenger craft, adopting a hybrid electric powering system and build with strip planking process for wooden ships. The description of the construction process will be here described together with the on-board electric power system. The integrated approach allowed
also to directly evaluate the vessel operative profile and asses whether the vessel could perform a Zero Emission Mode navigation.

This publication is available at IOS Press through this link


Extreme loads determination on complex slender structures

Authors: F. Mauro, L. Braidotti, U. la Monaca and R. Nabergoj
Abstract:

For the dimensioning of particular structures like stingers or generic tubular elements for offshore industry, it is usual to predict the extreme values of wave
induced loads. Both for model test and calculations, the traditionally adopted methods of analysis are based on Weibull distribution. The necessity to investigate severe sea state conditions together with the increased complexity of the structure is an evident source of non-linearities in the exciting force peaks distribution.
In the specific, the adoption of a standard Weibull approach is not indicated for
accurately predict the extreme loads. The adoption of more accurate distributions
suitable to capture peaks non-linearity will ensure to overcome or capture possible multi-modal behaviour of the considered population. These enhanced techniques can be used not only for model test results analysis, but also for results coming from preliminary hydrodynamic calculations (CFD). In the present work, two different methodologies based on Mixed Weibull and Generalised Pareto distributions will be applied to the results obtained for a stinger geometry, where Morison theory is adopted to evaluate wave loads considering shield effects between the single tubular elements.

This publication is available at IOS Press through this link


Numerical simulations of a cavitating propeller in uniform and oblique flow

Authors: M. Morgut, D. Jost, A. Skerlavaj, E. Nobile, G. Contento, R. Pigazzini, T. Puzzer and S. Martini
Abstract:

The numerical predictions of a cavitating model scale propeller working in uniform and oblique flow conditions are presented. The cavitating phenomena are numerically reproduced using a homogeneous (mixture) model where three previously calibrated mass transfer models are alternatively used to model the mass transfer rate. The turbulence effect is modelled using the Reynolds Averaged Navier Stokes (RANS) approach. The simulations are performed using an open source solver. The numerical results are compared with available experimental data. For a quantitative comparison the propeller thrust is considered, while for a qualitative comparison, snapshots of cavitation patterns are shown. The thrust values obtained with the three different mass transfer models are very close to each other, however differences in the predicted cavitation patterns are observed. Moreover, some discrepancies between the numerical results and experimental data are reported.

This publication is available at IOS Press through this link


Static and dynamic comparison of megayacht deck structure’s layouts

Authors: G. Vergassola, D. Boote and L. Ricci
Abstract:

The growing increase in length of super and megayachts has driven structural designers to adopt longitudinal layouts as a main point in the structural scantlings. By the way, the optimization of weights, strength, deformations and dynamic
behaviour has to be evaluated separately for each new unit because of the particular and unique characteristics of each vessel. For this evaluation, especially for what the dynamic behaviour of ribbed plates is concerned, the use of numerical
software based on the Finite Element Method is widely used since the early design stages in order to highlight benefits and weaknesses of a particular structural design. In this paper, two different structural layouts of megayacht decks have been
studied and tested by using a FE software: the first one has been created with longitudinal and transversal stiffeners with the same cross section. In the second layout, transversal stiffeners are smaller in dimension but with lower span. The
comparison has been carried out making reference to maximum strengths, deformations and dynamic behaviour. This work, starting from an initial lay out obtained by a CS rule approach, made it possible to converge to an optimal structural  configuration, at least for what the starting geometries are concerned.

This publication is available at IOS Press through this link


ISP Volume 65, nr 2

ISP Volume 65, issue 2 of 2018 contains 4 articles on various topics.
These range from the development of a Life Cycle ship Performance Assessment (LCPA) method, blending economic and environmental aspects, to numerical investigations of ship maneuvering, propeller performance and seakeeping behavior.
More extensive summaries, as well as the full articles can be found on
https://content.iospress.com/journals/international-shipbuilding-progress/65/2

Life cycle ship performance assessment (LCPA): A blended formulation between costs and environmental aspects for early design stage

Authors: P. Gualeni and M. Maggioncalda
Abstract:
GualThe development is described of a method to compare different design solutions in the early design stage with respect to performances along the whole life-cycle frame by a single parameter: the LCPA index. This index includes the impacts of bothaspects are identified and discussed. A blended formulation between Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) is developed, leading to the LCPA-index. A Ship Breakdown Structure has been developed to link ship design parameters with the calculation of KPIs. The approach has been implemented and applied to a Ro-Ro passenger ship in order to validate the LCPA tool structure and its reliability.

This publication is available at IOS Press through this link


Numerical investigation on the influence of Froude number on the maneuvering characteristics of a container ship

Authors: Rameessha, T.V. and Krishankutty, P.
Abstract:

Rameesha and KrishankuttyNumerical simulations are described of captive maneuvering model tests at different forward speeds for a containership to estimate the speed effect on the hydrodynamic derivatives.
It is shown that the effect of forward speed can be significant and should be taken into account when making predictions of maneuvering behavior.

This publication is available at IOS Press through this link

 


Improving model scale propeller performance prediction using the k-kL-ω transition model in OpenFOAM

Authors: Gaggero, S. and Villa, D.

Abstract:

Gaggero and Villa

Propeller performance on full scale is usually based on results of open water tests on model scale, which is usually scaled up to full scale by some semi-empirical method. In practice these appear not always to be sufficiently accurate, especially for special geometries like high skew propellers, propellers with tip rake, ducted propellers or CLT propellers. This article describes a CFD-based approach to calculate the performance of model scale propellers in open water, taking into account transition from laminar to turbulent flow. It is validated against results of experiments with three benchmark propellers and showed substantial improvements in the accuracy of the performance prediction, compared to calculations based on fully turbulent flow.

This publication is available at IOS Press through this link


CFD, potential flow and system-based simulations of fully appended free running 5415M in calm water and in waves

Authors: Toxopeus, S., Sadat-Hosseini, H., Visonneau, M., Guilmineau, E., Yen, T.-G., Lin, W.-M., Grigoropoulos, G. and Stern, F.

Abstract:
Toxopeus e.a.The seakeeping ability of ships is one of the aspects that needs to be assessed during the design phase of ships. Traditionally, potential flow calculations and model tests are employed to investigate whether the ship performs according to specified criteria. In the present paper, a detailed validation study of several computational methods for ship dynamics is presented. The ability of the methods to predict motions in calm water as well as in waves is investigated. In calm water, the roll decay behavior of a fully appended self-propelled free running 5415M model is investigated first. Subsequently, forced roll motions simulated by oscillating the rudders or stabilizer fins are studied. Lastly, the paper discusses comparisons between experiments and simulations in waves with varying levels of complexity, i.e. regular head waves, regular beam waves and bi-chromatic waves. The predictions for all methods are validated with an extensive experimental data set. The paper shows that only high-fidelity CFD is able to accurately predict all the relevant physics during roll decay, forced oscillation and sailing in waves.

This publication is available at IOS Press through this link


ISP Volume 65, nr 1

ISP Volume 65, issue 1 of 2018 contains 4 articles on various topics. These range from an experimental analysis of the seakeeping performance of catamaran forms with bulbous bows to a multiaxial fatigue assessment of welded joints in marine structures, a hydrostatic analyses of uprighting processes of capsized and damaged ships and wind-tunnel experiments on a aerodynamic interaction between two ridid sails used for wind assisted propulsion.
Summaries of these articles are provided below. These summaries, as well as the full articles can be found on https://content.iospress.com/journals/international-shipbuilding-progress/65/1 .


Experimental analysis of the seakeeping performance of catamaran forms with bulbous bows

Authors: Abdul Ghani, Pauzi| Wilson, Philip

Abstract: This paper explores the effects of adding different forms of bulbous bows onto catamaran hulls and assesses the implications on the seakeeping performance. There has been a large body of work that assess’ the effect of wave wake wash and recently studies have been undertaken to determine the effects of bulbous bows on reducing wave wake wash. However, not much research has been published on the effects of bulbous bows on the seakeeping performance of catamarans fitted with bulbous bows. This paper presents experimental results that will allow a ship designer to understand the effects of bulbous bows on heave, pitch and added resistance in waves. In conclusion it ranks the importance of different bulbous bows on the seakeeping performance.

This publication is available at IOS Press through this link


Multiaxial fatigue assessment of welded joints in marine structures

Authors: van Lieshout, P.S.| den Besten, J.H. | Kaminski, M.L.

Abstract: Structural geometry and stochastic loads such as swell and wind seas can typically induce multiaxial stress states in welded details of marine structures. It is known that such complex time varying stress states determine the fatigue resistance of welded steel joints. Therefore, it is of importance to account for them in fatigue lifetime estimation. Over the past few decades a wide variety of design guidelines and methods have been developed for multiaxial fatigue assessment, but so far there does not exist a general hypothesis applicable to all possible load cases. This study provides an overview of the current state-of-the-art in academia and engineering practice in terms of multiaxial fatigue assessment, and is focusing on the application to welded joints in marine structures. The progress of different approaches and methods is elaborated and commented upon, taking their hypothesis and (physical) basis into consideration. The insights that are provided in this paper form a valuable foundation for future investigations and emphasize the necessity of experimental proofs and model validation.

This publication is available at IOS Press through this link


Hydrostatic analyses of uprighting processes of a capsized and damaged ship

Abstract: In the process of marine salvage, the capsized ship is normally required to go through a process of righting firstly, which essentially means bringing the deck to point upwards. Calculation of the righting force is the key to achieving success in designing schemes. At present, the righting force calculation relies on the use of empirical formulae. However, their accuracy and reliability is not high. In this paper, a mathematical model of the flooding quantity and righting force was established based on the hydrostatic theory applied to the ship. A three-dimensional ship model was built via General Hydrostatics software (GHS) to simulate the uprighting process of a capsized and damaged ship. Four typical uprighting processes concerning capsized ships were simulated, namely the case where about 50% of the superstructure volume was filled with water (Case 1), where about 50% of the engine room volume was filled with water (Case 2), where the superstructure was detached (Case 3) and where a large amount of air in the damaged compartments existed (Case 4). Simulation results show that the proportion between the maximum righting moment and the maximum righting moment in the opposite direction is 0.459, 0.486, 0.424 and 0.346 for cases A, B, C and D, respectively. So a larger righting force moment in the opposite direction is needed to prevent the ship from being damaged again or from capsizing again. The shear force is not always increasing with the flooding quantity or displacement. The effect of flooding water distribution is more obvious than the flooding quantity and displacement for a ship with many damaged compartments when the trim angle variation is very small. Thus, the righting force can be efficiently reduced by designing reasonable uprighting schemes.

This publication is available at IOS Press through this link


Wind-tunnel experiments on the aerodynamic interaction between two rigid sails used for wind-assisted propulsion

This publication is available at IOS Press through this link


ISP Volume 64, nrs 1 and 2

ISP Volume 64, issue 1-2 of 2017 contains 6 articles on various topics. These range from applying RANS CFD methods to predict ship propulsive performance, to application of laminated glass in the yacht industry, ship stability during launching when applying pneumatic airbags, sloshing in LNG tanks and mitigation of bubble sweep down from a ship’s bow. Brief summaries of these articles are provided below. More extensive summaries, as well as the full articles can be found on https://content.iospress.com/journals/international-shipbuilding-progress/64/1-2.


Three-dimensional RANS method to numerically solve ship’s wave-making resistance compared with the Rankine source method

3D RANS

This article describes the application of a three-dimensional RANS CFD method to calculate the wave-making resistance of a Wigley hull and a Series 60 hull. The results are compared to results of calculations by a Rankine source boundary element method and results of model tests.

The here shown Illustration is reprinted from ISP, Vol number 64, Jun-ming Hu, Tie-li Li, Yan Lin, Guan Guan and Zhuo-shang Ji, Three-dimensional RANS method to numerically solve ship’s wave-making resistance compared with the Rankine source method, Pages No. 1-23, Copyright (2017), with permission from IOS Press.

 This publication is available at IOS Press through this link.


On the damping coefficient of laminated glass for yacht industry

Damping coefficient of glass

Very large glass surfaces, that are more and more applied on yachts, are critical elements as regards the assessment of the ship’s noise and vibration characteristics. This makes the laminated glass dynamic characterization a fundamental issue to be investigated. The article describes different experimental modal methods to obtain the damping coefficient at natural frequencies, applied to laminated glass specimens. The results of these methods are compared with each other.

The shown Illustration is reprinted from ISP, Vol number 64, D. Boote, T. Pais, G. Vergassola, A. Tonelli and L. Gragnani, On the damping coefficient of laminated glass for yacht industry, Pages No. 25-40, Copyright (2017), with permission from IOS Press.

This publication is available at IOS Press via this link


Ship stability analysis during launching from longitudinal sloping slipway by pneumatic airbags

This article presents a new analysis method of taking into account the possibility of a tanker tipping during launching on pneumatic airbags. Launching calculations and diagrams for both the traditional and pneumatic airbags launching are presented along with a comparative analysis of the two launching methods.

This publication is available at IOS Press via this link


 

Prediction of ship power and speed performance based on RANS method

Speedpower RANS

This article describes the application of CFD RANS methods to calculate the open water performance of a ducted propeller model for a fishing vessel, the resistance of the model of this vessel and the propulsive performance of this ship model when fitted with the subject propeller model. The results are compared with results of model tests.

The Illustration is reprinted from ISP, Vol number 64, Jun-ming Hu, Tie-li Li, Yan Lin, Guan Guan and Zi-bo Zheng, Prediction of ship power and speed performance based on RANS method, Pages No. 51-78, Copyright (2017), with permission from IOS Press.

This publication is available at IOS Press via this link.

 


A numerical technique for sloshing in an independent type C LNG tank with experimental investigation and validation

LNG Sloshing

Sloshing induced by partial loading is violent when a resonance condition occurs. Given strong nonlinearity, rapid and accurate prediction of sloshing loads under resonance conditions is the key factor in the design of LNG cargo tanks.
This article describes the application of a CFD technique to simulate sloshing, and experiments conducted to verify the results of the simulations. The results of both approaches are compared to each other.

This Illustration is reprinted from ISP, Vol number 64, Ge Liu, Yan Lin, Guan Guan and Yan-yun Yu, A numerical technique for sloshing in an independent type C LNG tank with experimental investigation and validation, Pages No. 79-100, Copyright (2017), with permission from IOS Press.

This publication is available at IOS Press via this link


Dydrodynamic design for mitigation of bubble sweep down in sonar mounted research vessels

Bubble sweep

 

Oceanographic research vessels are fitted with acoustic sonar transducers at the bottom keel region.
Bubbles that are swept down from the bow region interfere with the acoustic transmission and deteriorate the functioning of the sonar transducer. This article describes the development of a special bow shape, due to which the path of swept down bubbles is diverted away from the acoustic sonar transducer. This development includes the application of RANS CFD and experiments on model scale..

This Illustration is reprinted from ISP, Vol number 64, M. Palaniappan and V. Anantha Subramanian, Hydrodynamic design for mitigation of bubble sweep down in sonar mounted research vessels, Pages No. 101-126, Copyright (2017), with permission from IOS Press.

This publication is available at IOS Press via this link


ISP Volume 63, nrs 3 and 4

ISP logoOn this page, you will find short summaries of the articles included in the relevant editions of ISP Journal, per year and quarterly edition.
With each article you will find a link to the IOS press website, where you can read more about that article and the relevant edition and how to order it.

 

Back to the ISP Journal introduction page.

ISP Volume 63, numbers 3,4 of 2016/2017 is a special issue about the European Union (EU) project GRIP. GRIP stands for “Green Retrofitting through optimization of hull-Propulsion Interaction”. The project addressed several aspects of fitting Energy Saving Devices (ESD’S) to existing ships.

Aspects that were addressed are among others: the working principles of ESD’s, the development of an Early Assessment Tool (EAT) to estimate the energy saving potential of a specific ESD to a specific ship, structural aspects (loads, fatigue and vibrations), and the shipyard process to fit an ESD to a ship of which the hull geometry is not exactly known. Within the project a specific ESD has been designed, built and tested on full scale.

This ISP issue contains 9 articles, covering all aspects from estimating the power saving potential to the actual design and construction of ESD’s, fitting them to a ship and testing tem on full scale.

Summaries, as well as the complete contents of the articles included in ISP Volume 63, numbers 3,4 can be found via the IOS Press website via this link 

Back to the ISP Journal introduction page.

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