Pub Date : 2021-09-08DOI: 10.1080/09377255.2021.1966575
L. Birk
ABSTRACT In a series of landmark reports and papers, J.L. Hess and A.M.O. Smith of Douglas Aircraft Company, Inc. introduced the quadrilateral constant source panel to solve three-dimensional nonlifting potential flow problems. Later a panel with constant dipole (doublet) distribution was added for lifting flow computations. Hess and Smith's publications provide equations for the computation of the velocities induced by the singularity distributions along with required geometric properties of the panel. Equations are presented considering an implementation in Fortran (Versions II and IV), the commonly used programming language for numerical methods at the time. The present paper builds on Hess and Smith's groundbreaking work, restating equations with modern programming languages in mind capable of fast vector operations like Fortran 95, Python or Julia. Formulas are provided for the computation of geometric properties, coordinate transformations, as well as first and second-order potential derivatives. Example input and output data allow readers to test and validate their own implementation.
{"title":"A comprehensive and practical guide to the Hess and Smith constant source and dipole panel","authors":"L. Birk","doi":"10.1080/09377255.2021.1966575","DOIUrl":"https://doi.org/10.1080/09377255.2021.1966575","url":null,"abstract":"ABSTRACT In a series of landmark reports and papers, J.L. Hess and A.M.O. Smith of Douglas Aircraft Company, Inc. introduced the quadrilateral constant source panel to solve three-dimensional nonlifting potential flow problems. Later a panel with constant dipole (doublet) distribution was added for lifting flow computations. Hess and Smith's publications provide equations for the computation of the velocities induced by the singularity distributions along with required geometric properties of the panel. Equations are presented considering an implementation in Fortran (Versions II and IV), the commonly used programming language for numerical methods at the time. The present paper builds on Hess and Smith's groundbreaking work, restating equations with modern programming languages in mind capable of fast vector operations like Fortran 95, Python or Julia. Formulas are provided for the computation of geometric properties, coordinate transformations, as well as first and second-order potential derivatives. Example input and output data allow readers to test and validate their own implementation.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"69 1","pages":"50 - 62"},"PeriodicalIF":2.2,"publicationDate":"2021-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43023749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-05DOI: 10.1080/09377255.2021.1973263
Himabindu Allaka, Morel Groper
ABSTRACT High-speed planing craft operating in real seaways encounter high impact loads. The extreme motions and accelerations resulting from such impacts adversely affect the structure of the craft and its payload as well as pose a risk to the crew on-board. Limiting craft speed according to the sea state using a speed-wave height operational envelope might ensure structural integrity and greatly improve safe navigation. Accurate estimation of motion and acceleration of planing craft in a seaway is a key requirement in developing reliable and usable allowable speed vs. wave height operational curves. In this paper, the Motion Assessment of Planing Craft in a Seaway (MAPCS) tool, a nonlinear time-domain approach vs. several existing approaches based on experimental, empirical and classification societies’ formulas for vertical accelerations and speed vs. wave height limit curves are compared. It is found that the MAPCS approach provides more realistic estimations compared to the commonly employed methods.
{"title":"Speed–wave height operational envelope for high-speed planing craft in seaways: theoretical vs. empirical methods","authors":"Himabindu Allaka, Morel Groper","doi":"10.1080/09377255.2021.1973263","DOIUrl":"https://doi.org/10.1080/09377255.2021.1973263","url":null,"abstract":"ABSTRACT High-speed planing craft operating in real seaways encounter high impact loads. The extreme motions and accelerations resulting from such impacts adversely affect the structure of the craft and its payload as well as pose a risk to the crew on-board. Limiting craft speed according to the sea state using a speed-wave height operational envelope might ensure structural integrity and greatly improve safe navigation. Accurate estimation of motion and acceleration of planing craft in a seaway is a key requirement in developing reliable and usable allowable speed vs. wave height operational curves. In this paper, the Motion Assessment of Planing Craft in a Seaway (MAPCS) tool, a nonlinear time-domain approach vs. several existing approaches based on experimental, empirical and classification societies’ formulas for vertical accelerations and speed vs. wave height limit curves are compared. It is found that the MAPCS approach provides more realistic estimations compared to the commonly employed methods.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"46 - 55"},"PeriodicalIF":2.2,"publicationDate":"2021-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42294435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-05DOI: 10.1080/09377255.2021.1973264
I. Gypa, Marcus Jansson, Krister Wolff, R. Bensow
ABSTRACT Marine propeller design can be carried out with the aid of automated optimization, but experience shows that a such an approach has still been inferior to manual design in industrial scenarios. In this study, the automated propeller design optimization is evolved by integrating human–computer interaction as an intermediate step. An interactive optimization methodology, based on interactive genetic algorithms (IGAs), has been developed, where the blade designers systematically guide a genetic algorithm towards the objectives. The designers visualize and assess the shape of the blade cavitation and this evaluation is integrated in the optimization method. The IGA is further integrated with a support-vector machine model, in order to avoid user fatigue, IGA's main disadvantage. The results of the present study show that the IGA optimization searches solutions in a more targeted manner and eventually finds more non-dominated feasible designs that also show a good cavitation behaviour in agreement with designer preference.
{"title":"Propeller optimization by interactive genetic algorithms and machine learning","authors":"I. Gypa, Marcus Jansson, Krister Wolff, R. Bensow","doi":"10.1080/09377255.2021.1973264","DOIUrl":"https://doi.org/10.1080/09377255.2021.1973264","url":null,"abstract":"ABSTRACT Marine propeller design can be carried out with the aid of automated optimization, but experience shows that a such an approach has still been inferior to manual design in industrial scenarios. In this study, the automated propeller design optimization is evolved by integrating human–computer interaction as an intermediate step. An interactive optimization methodology, based on interactive genetic algorithms (IGAs), has been developed, where the blade designers systematically guide a genetic algorithm towards the objectives. The designers visualize and assess the shape of the blade cavitation and this evaluation is integrated in the optimization method. The IGA is further integrated with a support-vector machine model, in order to avoid user fatigue, IGA's main disadvantage. The results of the present study show that the IGA optimization searches solutions in a more targeted manner and eventually finds more non-dominated feasible designs that also show a good cavitation behaviour in agreement with designer preference.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"56 - 71"},"PeriodicalIF":2.2,"publicationDate":"2021-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46390430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-03DOI: 10.1080/09377255.2021.1962680
A. Papanikolaou
It is my pleasure to present you a review of the recently published book of Springer Nature on ‘Numerical Methods for Seakeeping Problems’. The three co-authors of the book are internationally renowned experts in the development of numerical methods/software tools and their use in solving practical problems of seakeeping of ships and floating structures. The material of the book is to a large extent based on lectures held at the Technical University Hamburg-Harburg and the University of Duisburg-Essen, as well as on cited publications of the authors. Even more, all three authors have many years of experience with the service work of a major classification society (Germanischer Lloyd), when they supported the needs of the international maritime industry. Whereas in the past the knowledge of ship’s seakeeping was considered of prime importance only for special types of ships (e.g. naval ships), when compared to ship’s calm water performance and stability, it is not so nowadays in view of enhanced requirements for ship’s operation in realistic sea conditions and the safety of ships, of people onboard and cargo related to ship’s dynamic (intact and damage) stability. Even more, the recently introduced international regulations for the reduction of Green House Gas emissions, affecting both ship’s design and operation, call for methods and tools to assess ship’s performance in realistic sea conditions. The gained knowledge from the longstanding development of efficient numerical methods and software tools, along with their practical use, are presented in this book by a renowned team of experts and will be briefly commented in the following. The book consists of 17 chapters. After a brief introduction into the subject of the book in chapter 1, while considering marine accidents that were affected by adverse weather conditions, the theory of seakeeping is gradually introduced by first presenting the governing fundamental equations of fluid flow (incompressible viscous and ideal fluids) and the rigid body motions (nonlinear and linearized equations of motion) in chapter 2. In chapter 3, fundamental numerical methods for the incompressible potential flows (with and without lift) are presented, along with a demonstration software tool for the two-dimensional flow around a smooth body without lift. In chapter 4 the basic theory of regular and irregular water waves is introduced, while considering the linear superposition principle and spectral analysis techniques for the simulation of linear and nonlinear natural seaways and their ensuing statistics of important parameters. In chapter 5, quasi two-dimensional strip theory seakeeping methods are elaborated, starting with a brief history of developments after the fundamental work of F. Ursell in 1949. Strip theory methods became very popular over the years due to their low computational effort and the wide dissemination of the ensuing theory and numerical implementation. The linear and nonlinear computation of
{"title":"Numerical methods for seakeeping problems","authors":"A. Papanikolaou","doi":"10.1080/09377255.2021.1962680","DOIUrl":"https://doi.org/10.1080/09377255.2021.1962680","url":null,"abstract":"It is my pleasure to present you a review of the recently published book of Springer Nature on ‘Numerical Methods for Seakeeping Problems’. The three co-authors of the book are internationally renowned experts in the development of numerical methods/software tools and their use in solving practical problems of seakeeping of ships and floating structures. The material of the book is to a large extent based on lectures held at the Technical University Hamburg-Harburg and the University of Duisburg-Essen, as well as on cited publications of the authors. Even more, all three authors have many years of experience with the service work of a major classification society (Germanischer Lloyd), when they supported the needs of the international maritime industry. Whereas in the past the knowledge of ship’s seakeeping was considered of prime importance only for special types of ships (e.g. naval ships), when compared to ship’s calm water performance and stability, it is not so nowadays in view of enhanced requirements for ship’s operation in realistic sea conditions and the safety of ships, of people onboard and cargo related to ship’s dynamic (intact and damage) stability. Even more, the recently introduced international regulations for the reduction of Green House Gas emissions, affecting both ship’s design and operation, call for methods and tools to assess ship’s performance in realistic sea conditions. The gained knowledge from the longstanding development of efficient numerical methods and software tools, along with their practical use, are presented in this book by a renowned team of experts and will be briefly commented in the following. The book consists of 17 chapters. After a brief introduction into the subject of the book in chapter 1, while considering marine accidents that were affected by adverse weather conditions, the theory of seakeeping is gradually introduced by first presenting the governing fundamental equations of fluid flow (incompressible viscous and ideal fluids) and the rigid body motions (nonlinear and linearized equations of motion) in chapter 2. In chapter 3, fundamental numerical methods for the incompressible potential flows (with and without lift) are presented, along with a demonstration software tool for the two-dimensional flow around a smooth body without lift. In chapter 4 the basic theory of regular and irregular water waves is introduced, while considering the linear superposition principle and spectral analysis techniques for the simulation of linear and nonlinear natural seaways and their ensuing statistics of important parameters. In chapter 5, quasi two-dimensional strip theory seakeeping methods are elaborated, starting with a brief history of developments after the fundamental work of F. Ursell in 1949. Strip theory methods became very popular over the years due to their low computational effort and the wide dissemination of the ensuing theory and numerical implementation. The linear and nonlinear computation of","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"69 1","pages":"63 - 64"},"PeriodicalIF":2.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1962680","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46780497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-20DOI: 10.1080/09377255.2021.1954835
H. Yasukawa, N. Hirata, Y. Nakayama, A. Matsuda
ABSTRACT The drift characteristics in wind of a dead ship that cannot sail on its own are investigated experimentally and theoretically. First, a free-drift test of a bulk carrier model in wind is conducted. Next, a time-domain simulation method is developed for predicting the drift motion of the dead ship in wind. Tank tests and motion simulations show that the dead ship drifts with a large hull drift angle over in wind, and the converged drift angle is independent of wind speed and initial ship heading angle. To explain why the dead ship drifts with a large drift angle in wind, a theoretical formula is derived for investigating the motion stability of the dead ship in wind. It is theoretically confirmed that the ship drifts stably with a large drift angle over in wind, whereas drift angles of and result in unstable motion. Thus the reason for the drift behaviour of the dead ship is clarified.
{"title":"Drifting of a dead ship in wind","authors":"H. Yasukawa, N. Hirata, Y. Nakayama, A. Matsuda","doi":"10.1080/09377255.2021.1954835","DOIUrl":"https://doi.org/10.1080/09377255.2021.1954835","url":null,"abstract":"ABSTRACT The drift characteristics in wind of a dead ship that cannot sail on its own are investigated experimentally and theoretically. First, a free-drift test of a bulk carrier model in wind is conducted. Next, a time-domain simulation method is developed for predicting the drift motion of the dead ship in wind. Tank tests and motion simulations show that the dead ship drifts with a large hull drift angle over in wind, and the converged drift angle is independent of wind speed and initial ship heading angle. To explain why the dead ship drifts with a large drift angle in wind, a theoretical formula is derived for investigating the motion stability of the dead ship in wind. It is theoretically confirmed that the ship drifts stably with a large drift angle over in wind, whereas drift angles of and result in unstable motion. Thus the reason for the drift behaviour of the dead ship is clarified.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"26 - 45"},"PeriodicalIF":2.2,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1954835","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42036406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-06DOI: 10.1080/09377255.2021.1947666
M. Aguiari, M. Gaiotti, C. Rizzo
ABSTRACT Hull weight is a design parameter affecting the whole performances of a ship, being related to building costs, operational costs, maintenance and durability, and not least to satisfaction of functional requirements. Naval ships are no exception and impact of hull weight is crucial to fulfil mission requirements. In the light of the above, weight reduction is one of the main design drivers and it should be duly accounted for since the concept design phase. In this paper, a design approach intended for pre-contractual design phases is presented. It takes advantage of recent developments and trends of construction rules as well as of nowadays-available computation potential to update and improve the traditional scantling design approach, applied since decades by designers. The complexity and computational burden is kept to a minimum to provide a user-friendly procedure applicable in everyday working practice. Designers’ experience and judgment continue to drive the whole process. A Visual Basic support software has been developed with worksheet interfaces to implement the proposed scantling design procedure. Test cases showed significant weight reductions with respect to as-built ships and to scantling obtained by applying traditional design procedures.
{"title":"A design approach to reduce hull weight of naval ships","authors":"M. Aguiari, M. Gaiotti, C. Rizzo","doi":"10.1080/09377255.2021.1947666","DOIUrl":"https://doi.org/10.1080/09377255.2021.1947666","url":null,"abstract":"ABSTRACT Hull weight is a design parameter affecting the whole performances of a ship, being related to building costs, operational costs, maintenance and durability, and not least to satisfaction of functional requirements. Naval ships are no exception and impact of hull weight is crucial to fulfil mission requirements. In the light of the above, weight reduction is one of the main design drivers and it should be duly accounted for since the concept design phase. In this paper, a design approach intended for pre-contractual design phases is presented. It takes advantage of recent developments and trends of construction rules as well as of nowadays-available computation potential to update and improve the traditional scantling design approach, applied since decades by designers. The complexity and computational burden is kept to a minimum to provide a user-friendly procedure applicable in everyday working practice. Designers’ experience and judgment continue to drive the whole process. A Visual Basic support software has been developed with worksheet interfaces to implement the proposed scantling design procedure. Test cases showed significant weight reductions with respect to as-built ships and to scantling obtained by applying traditional design procedures.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"69 1","pages":"89 - 104"},"PeriodicalIF":2.2,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1947666","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46995777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.1080/09377255.2021.1934362
S. Gaggero, M. Martinelli
ABSTRACT Pre- and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (pre-swirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.
{"title":"Pre- and post-swirl fins design for improved propulsive performances","authors":"S. Gaggero, M. Martinelli","doi":"10.1080/09377255.2021.1934362","DOIUrl":"https://doi.org/10.1080/09377255.2021.1934362","url":null,"abstract":"ABSTRACT\u0000 Pre- and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (pre-swirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"69 1","pages":"31 - 49"},"PeriodicalIF":2.2,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1934362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48572134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-17DOI: 10.1080/09377255.2021.1927590
Savas Sezen, M. Atlar
ABSTRACT This study focuses on the investigation of cavitating flow around the benchmark INSEAN E779A model propeller with the main aim of further improving the computational efficiency of the tip vortex cavitation (TVC) modelling by using a commercial CFD solver. Also, the effects of various key computational parameters including, numerical modelling, grid size, timestep, water quality and boundary layer resolution, on the TVC formation and its extension in the propeller slipstream are investigated systematically. The numerical simulations are conducted in uniform and open water conditions using RANS, DES and LES solvers implemented in the commercial CFD code, Start CCM+. In order to achieve the aim of the study, an alternative and new Vorticity-based Adaptive Mesh Refinement (V-AMR) technique is introduced for enhanced modelling of the TVC on the blades and downstream. For the CFD modelling of cavitation, the Schneer Sauer cavitation model based on the reduced Rayleigh Plesset equation is used for the sheet, tip and hub vortex cavitation. The hydrodynamic results and cavity patterns are validated with the experimental data. The results show that the application of the V-AMR technique further improves the representation of the TVC with minimal increase in computational cost. However, the eddy viscosity at the propeller blade tips increases with applying the V-AMR technique using the RANS solver due to its inherent modelling errors for the solution of the flow inside the tip vortex. This consequently results in an insufficient extension of TVC in the propeller slipstream compared to the predictions by the DES and LES based numerical solvers. Also, the evolution of the TVC is found to be sensitive to the boundary layer resolution when the standard RANS solver is used. The study will help to widen further applications of the CFD methods involving TVC, particularly for propeller induced underwater noise prediction and analysis.
{"title":"An alternative Vorticity based Adaptive Mesh Refinement (V-AMR) technique for tip vortex cavitation modelling of propellers using CFD methods","authors":"Savas Sezen, M. Atlar","doi":"10.1080/09377255.2021.1927590","DOIUrl":"https://doi.org/10.1080/09377255.2021.1927590","url":null,"abstract":"ABSTRACT This study focuses on the investigation of cavitating flow around the benchmark INSEAN E779A model propeller with the main aim of further improving the computational efficiency of the tip vortex cavitation (TVC) modelling by using a commercial CFD solver. Also, the effects of various key computational parameters including, numerical modelling, grid size, timestep, water quality and boundary layer resolution, on the TVC formation and its extension in the propeller slipstream are investigated systematically. The numerical simulations are conducted in uniform and open water conditions using RANS, DES and LES solvers implemented in the commercial CFD code, Start CCM+. In order to achieve the aim of the study, an alternative and new Vorticity-based Adaptive Mesh Refinement (V-AMR) technique is introduced for enhanced modelling of the TVC on the blades and downstream. For the CFD modelling of cavitation, the Schneer Sauer cavitation model based on the reduced Rayleigh Plesset equation is used for the sheet, tip and hub vortex cavitation. The hydrodynamic results and cavity patterns are validated with the experimental data. The results show that the application of the V-AMR technique further improves the representation of the TVC with minimal increase in computational cost. However, the eddy viscosity at the propeller blade tips increases with applying the V-AMR technique using the RANS solver due to its inherent modelling errors for the solution of the flow inside the tip vortex. This consequently results in an insufficient extension of TVC in the propeller slipstream compared to the predictions by the DES and LES based numerical solvers. Also, the evolution of the TVC is found to be sensitive to the boundary layer resolution when the standard RANS solver is used. The study will help to widen further applications of the CFD methods involving TVC, particularly for propeller induced underwater noise prediction and analysis.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"69 1","pages":"1 - 21"},"PeriodicalIF":2.2,"publicationDate":"2021-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1927590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46447586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-12DOI: 10.1080/09377255.2021.1925047
M. Tsujimoto, H. Yasukawa, Kotaku Yamamoto, Tae-il Lee
ABSTRACT With the start of the EEDI (energy efficiency design index for new ships) regulations by the International Maritime Organization, a review of the analysis method for speed/power trials was required. The International Towing Tank Conference (ITTC) Specialist Committee on Performance of Ships in Service has conducted a review since 2011. For wave correction in speed/power trials, various methods were validated to improve correction accuracy during the activities. In this paper, the process of validation and implementation of the wave correction method discussed through the committee is shown. The comparison based on the results of tank test in regular waves, tank test in long-crested irregular waves and speed/power trials of full-scale ships has been examined. From the studies, the features of each method of wave correction are understood, which is helpful for the implementation of the wave correction performed in speed/power trials.
{"title":"Validation of added resistance in waves by tank tests and sea trial data","authors":"M. Tsujimoto, H. Yasukawa, Kotaku Yamamoto, Tae-il Lee","doi":"10.1080/09377255.2021.1925047","DOIUrl":"https://doi.org/10.1080/09377255.2021.1925047","url":null,"abstract":"ABSTRACT With the start of the EEDI (energy efficiency design index for new ships) regulations by the International Maritime Organization, a review of the analysis method for speed/power trials was required. The International Towing Tank Conference (ITTC) Specialist Committee on Performance of Ships in Service has conducted a review since 2011. For wave correction in speed/power trials, various methods were validated to improve correction accuracy during the activities. In this paper, the process of validation and implementation of the wave correction method discussed through the committee is shown. The comparison based on the results of tank test in regular waves, tank test in long-crested irregular waves and speed/power trials of full-scale ships has been examined. From the studies, the features of each method of wave correction are understood, which is helpful for the implementation of the wave correction performed in speed/power trials.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"14 - 25"},"PeriodicalIF":2.2,"publicationDate":"2021-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1925047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47356780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-04DOI: 10.1080/09377255.2020.1815140
Í. A. Fonseca, H. Gaspar
ABSTRACT A digital twin is a digital asset that simulates the behaviours of a physical counterpart. Digital twin ship literature identifies that the concept is already being applied to specialised problems, but no clear guide exists for creating broader interdisciplinary digital twins. Relevant dimensions of product data modelling and previous attempts at standardizing ship data elucidate the requirements for effective data modelling in a digital twin context. Such requirements are placed in a broader perspective for digital twin implementation that encompasses challenges and directions for future development of services, networks, and software. Finally, an open standardization for digital twin data is proposed based on lessons extracted from this panorama, proposing its application to a research vessel.
{"title":"Challenges when creating a cohesive digital twin ship: a data modelling perspective","authors":"Í. A. Fonseca, H. Gaspar","doi":"10.1080/09377255.2020.1815140","DOIUrl":"https://doi.org/10.1080/09377255.2020.1815140","url":null,"abstract":"ABSTRACT A digital twin is a digital asset that simulates the behaviours of a physical counterpart. Digital twin ship literature identifies that the concept is already being applied to specialised problems, but no clear guide exists for creating broader interdisciplinary digital twins. Relevant dimensions of product data modelling and previous attempts at standardizing ship data elucidate the requirements for effective data modelling in a digital twin context. Such requirements are placed in a broader perspective for digital twin implementation that encompasses challenges and directions for future development of services, networks, and software. Finally, an open standardization for digital twin data is proposed based on lessons extracted from this panorama, proposing its application to a research vessel.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"68 1","pages":"70 - 83"},"PeriodicalIF":2.2,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1815140","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45617368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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