Pub Date : 2023-08-29DOI: 10.1080/09377255.2023.2250648
G. Anagnostopoulos, P. Kaklis
{"title":"Naval ship design-process analysis through dynamic social networks","authors":"G. Anagnostopoulos, P. Kaklis","doi":"10.1080/09377255.2023.2250648","DOIUrl":"https://doi.org/10.1080/09377255.2023.2250648","url":null,"abstract":"","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43099201","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 : 2023-04-10DOI: 10.1080/09377255.2023.2196042
L. Ferreiro
{"title":"Naval architecture saved The United States at its birth","authors":"L. Ferreiro","doi":"10.1080/09377255.2023.2196042","DOIUrl":"https://doi.org/10.1080/09377255.2023.2196042","url":null,"abstract":"","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46324424","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 : 2023-03-15DOI: 10.1080/09377255.2023.2184049
R. Hamann, J. Cichowicz
ABSTRACT The International Maritime Organization rule-making process utilizes a set of guidelines for the so-called Formal Safety Assessment (FSA). This process is based on a risk assessment and its purpose is to ensure that the risk to human health and life and to marine environment is tolerable. A central instrument in the FSA methodology is known as ALARP (As Low As Reasonably Practicable) principle which ensures that the risk is controlled in a rational and cost-effective manner. The FSA Guidelines recommend the use of monetary thresholds for performing the cost evaluation and provide an example of indices for measuring the cost efficiency. For risks involving fatalities, these measures require the use of a monetary threshold derived from the concept of Cost of Averting a Fatality (CAF). Due to the linkage to economic parameters, this threshold needs to be updated regularly to allow for correct cost-benefit assessment in the FSA context.
{"title":"Updating threshold for IMO cost-benefit assessment","authors":"R. Hamann, J. Cichowicz","doi":"10.1080/09377255.2023.2184049","DOIUrl":"https://doi.org/10.1080/09377255.2023.2184049","url":null,"abstract":"ABSTRACT The International Maritime Organization rule-making process utilizes a set of guidelines for the so-called Formal Safety Assessment (FSA). This process is based on a risk assessment and its purpose is to ensure that the risk to human health and life and to marine environment is tolerable. A central instrument in the FSA methodology is known as ALARP (As Low As Reasonably Practicable) principle which ensures that the risk is controlled in a rational and cost-effective manner. The FSA Guidelines recommend the use of monetary thresholds for performing the cost evaluation and provide an example of indices for measuring the cost efficiency. For risks involving fatalities, these measures require the use of a monetary threshold derived from the concept of Cost of Averting a Fatality (CAF). Due to the linkage to economic parameters, this threshold needs to be updated regularly to allow for correct cost-benefit assessment in the FSA context.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"239 - 248"},"PeriodicalIF":2.2,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47902749","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 : 2023-03-07DOI: 10.1080/09377255.2023.2180241
H. Söding
ABSTRACT Accurate predictions of the behavior of ships in steep regular waves or in a natural seaway must take into account nonlinear wave responses, especially for roll motions, section moments, and hull vibration excitation. In contrast to CFD methods, here fully nonlinear seakeeping simulations are presented based on potential flow with empirical corrections. This reduces the computing effort by several orders of magnitude. Comparisons with other calculations and model experiments for benchmark cases show that the accuracy of the present method is not worse than that of the best other computations and model experiments. After about ten years of development, the method appears mature for routine applications. The source code of the program is available from the author if an adequate gift is donated to the Mèdecins Sans Frontières.
{"title":"Nonlinear seakeeping and hydroelasticity of ships using potential flow simulations","authors":"H. Söding","doi":"10.1080/09377255.2023.2180241","DOIUrl":"https://doi.org/10.1080/09377255.2023.2180241","url":null,"abstract":"ABSTRACT Accurate predictions of the behavior of ships in steep regular waves or in a natural seaway must take into account nonlinear wave responses, especially for roll motions, section moments, and hull vibration excitation. In contrast to CFD methods, here fully nonlinear seakeeping simulations are presented based on potential flow with empirical corrections. This reduces the computing effort by several orders of magnitude. Comparisons with other calculations and model experiments for benchmark cases show that the accuracy of the present method is not worse than that of the best other computations and model experiments. After about ten years of development, the method appears mature for routine applications. The source code of the program is available from the author if an adequate gift is donated to the Mèdecins Sans Frontières.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"147 - 162"},"PeriodicalIF":2.2,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45476542","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 : 2023-01-17DOI: 10.1080/09377255.2023.2167537
Luofeng Huang, B. Pena, Giles Thomas
ABSTRACT Computational Fluid Dynamics (CFD) simulations of a ship’s operations are generally conducted at model scale, but the reduced scale changes the fluid behaviour around the ship. Whilst ideally ship simulations should be run directly at full scale, a guide has not been published to advise on the suitable setups that can provide accurate results while minimizing the computational cost. To address this, the present work explores an optimal approach for full-scale ship simulations. Extensive sensitivity studies were conducted on relevant computational setups to investigate their influences on the prediction of ship resistance, ship-generated waves as well as the boundary-layer flow of the hull. A set of CFD setups for full-scale ship simulations in open water was recommended. It was demonstrated that the ideal Y+ and Courant numbers in full scale are evidently different from those given in current model-scale CFD guidelines, indicating the necessity to establish full-scale CFD guidelines separately.
{"title":"Towards a full-scale CFD guideline for simulating a ship advancing in open water","authors":"Luofeng Huang, B. Pena, Giles Thomas","doi":"10.1080/09377255.2023.2167537","DOIUrl":"https://doi.org/10.1080/09377255.2023.2167537","url":null,"abstract":"ABSTRACT Computational Fluid Dynamics (CFD) simulations of a ship’s operations are generally conducted at model scale, but the reduced scale changes the fluid behaviour around the ship. Whilst ideally ship simulations should be run directly at full scale, a guide has not been published to advise on the suitable setups that can provide accurate results while minimizing the computational cost. To address this, the present work explores an optimal approach for full-scale ship simulations. Extensive sensitivity studies were conducted on relevant computational setups to investigate their influences on the prediction of ship resistance, ship-generated waves as well as the boundary-layer flow of the hull. A set of CFD setups for full-scale ship simulations in open water was recommended. It was demonstrated that the ideal Y+ and Courant numbers in full scale are evidently different from those given in current model-scale CFD guidelines, indicating the necessity to establish full-scale CFD guidelines separately.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"222 - 238"},"PeriodicalIF":2.2,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47174781","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 : 2022-12-24DOI: 10.1080/09377255.2022.2159108
H. Bakka, Hanne Rognebakke, I. Glad, Ingrid Hobæk Haff, E. Vanem
ABSTRACT Marine biofouling on a ship's hull and propeller increases the resistance of the ship moving through water and reduces the propulsion efficiency of the ship. Estimating the effect of fouling is difficult, as the biomass is rarely measured. In this paper, we present a new data-driven model for the total shaft power use of a large containership, in order to estimate the unobserved effect of fouling. Due to the limitations of both physical models and machine learning models, we develop a Bayesian generalized additive model for our purpose. We discuss issues of representative training data for the model. Further, we subset and subsample the data to a representative sample. Models are compared by out-of-sample predictive quality, physical appropriateness, and through autocorrelation of residuals. The Bayesian generalized additive model combined with computational inference using integrated nested Laplace approximations gives a robust estimate of the biofouling effect over time. It also allows a decomposition of the total shaft power use into effects of speed, weather, and other conditions. This model can be used to understand the effectiveness and timing of different hull and propeller treatments.
{"title":"Estimating the effect of biofouling on ship shaft power based on sensor measurements","authors":"H. Bakka, Hanne Rognebakke, I. Glad, Ingrid Hobæk Haff, E. Vanem","doi":"10.1080/09377255.2022.2159108","DOIUrl":"https://doi.org/10.1080/09377255.2022.2159108","url":null,"abstract":"ABSTRACT Marine biofouling on a ship's hull and propeller increases the resistance of the ship moving through water and reduces the propulsion efficiency of the ship. Estimating the effect of fouling is difficult, as the biomass is rarely measured. In this paper, we present a new data-driven model for the total shaft power use of a large containership, in order to estimate the unobserved effect of fouling. Due to the limitations of both physical models and machine learning models, we develop a Bayesian generalized additive model for our purpose. We discuss issues of representative training data for the model. Further, we subset and subsample the data to a representative sample. Models are compared by out-of-sample predictive quality, physical appropriateness, and through autocorrelation of residuals. The Bayesian generalized additive model combined with computational inference using integrated nested Laplace approximations gives a robust estimate of the biofouling effect over time. It also allows a decomposition of the total shaft power use into effects of speed, weather, and other conditions. This model can be used to understand the effectiveness and timing of different hull and propeller treatments.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"209 - 221"},"PeriodicalIF":2.2,"publicationDate":"2022-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43803410","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 : 2022-11-29DOI: 10.1080/09377255.2022.2149090
Z. Kok, J. Duffy, S. Chai, Yuting Jin
ABSTRACT An extensive Computational Fluid Dynamics (CFD) based study has been undertaken to develop a set of empirical formulae for squat prediction suitable for modern container ships in laterally-unrestricted shallow water. Previous work has quantified the effect of various ship principal particulars on midship sinkage and trim. The current study expands on the previous work to provide further quantifications for ship speed and water depth. Multiple linear regression analysis is then performed on the dataset to produce empirical equations for sinkage and trim. Predictions using the new set of formulae correlate well with the original dataset as well as new datasets which are within the limits of applicability. Predictions using the new formulae tend to be more accurate than existing empirical methods for the cases tested. Hence, the new set of formulae is a useful tool to provide reliable, rapid squat assessment and is suitable for implementation into real-time ship-handling simulator mathematical models.
{"title":"CFD-based empirical formulae for squat prediction of modern container ships","authors":"Z. Kok, J. Duffy, S. Chai, Yuting Jin","doi":"10.1080/09377255.2022.2149090","DOIUrl":"https://doi.org/10.1080/09377255.2022.2149090","url":null,"abstract":"ABSTRACT An extensive Computational Fluid Dynamics (CFD) based study has been undertaken to develop a set of empirical formulae for squat prediction suitable for modern container ships in laterally-unrestricted shallow water. Previous work has quantified the effect of various ship principal particulars on midship sinkage and trim. The current study expands on the previous work to provide further quantifications for ship speed and water depth. Multiple linear regression analysis is then performed on the dataset to produce empirical equations for sinkage and trim. Predictions using the new set of formulae correlate well with the original dataset as well as new datasets which are within the limits of applicability. Predictions using the new formulae tend to be more accurate than existing empirical methods for the cases tested. Hence, the new set of formulae is a useful tool to provide reliable, rapid squat assessment and is suitable for implementation into real-time ship-handling simulator mathematical models.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"174 - 189"},"PeriodicalIF":2.2,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41787176","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 : 2022-11-23DOI: 10.1080/09377255.2022.2149094
R. Suzuki, Y. Tsukada, M. Ueno
ABSTRACT We investigated the effects of the steady wave force variations generated by oblique motions upon ship manoeuvre estimations, using a numerical simulation that incorporated only steady wave forces into a three-degrees-of-freedom conventional modular mathematical model in calm water. The investigation was conducted for a very large crude carrier undergoing course-keeping manoeuvres in regular short waves. The steady wave forces in the simulation were provided via two methods, depending on the experimental data and the presence or absence of a ship drift angle. The simulation was validated via a free-running model test; this involved various rudder effectiveness conditions for the ship model and full-scale ships, both with and without engine limits. Through this validation, we showed that the steady wave force variations generated by oblique motions are non-negligible when accurately estimating the manoeuvres of full-scale ships in short waves, although they are negligible for ship models.
{"title":"Effects of steady wave forces on course-keeping manoeuvres of full- and model-scale ships moving obliquely in short waves","authors":"R. Suzuki, Y. Tsukada, M. Ueno","doi":"10.1080/09377255.2022.2149094","DOIUrl":"https://doi.org/10.1080/09377255.2022.2149094","url":null,"abstract":"ABSTRACT We investigated the effects of the steady wave force variations generated by oblique motions upon ship manoeuvre estimations, using a numerical simulation that incorporated only steady wave forces into a three-degrees-of-freedom conventional modular mathematical model in calm water. The investigation was conducted for a very large crude carrier undergoing course-keeping manoeuvres in regular short waves. The steady wave forces in the simulation were provided via two methods, depending on the experimental data and the presence or absence of a ship drift angle. The simulation was validated via a free-running model test; this involved various rudder effectiveness conditions for the ship model and full-scale ships, both with and without engine limits. Through this validation, we showed that the steady wave force variations generated by oblique motions are non-negligible when accurately estimating the manoeuvres of full-scale ships in short waves, although they are negligible for ship models.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"190 - 208"},"PeriodicalIF":2.2,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42064808","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 : 2022-10-28DOI: 10.1080/09377255.2022.2115241
D. Fuentes, A. Cura Hochbaum, R. Schulze
ABSTRACT The increasing interest in using flexible materials to design marine propellers, considering deformations due to flow loads. A numerical procedure for analysing two-way fluid-structure interactions, based on the commercial STAR-CCM+ multiphysics software, is described and applied to predict the hydroelastic response of the flexible marine propeller P1790 to hydrodynamic forces in open water conditions. The influence of the deformation on the performance of the flexible propeller was analysed by comparison with its rigid counterpart. The procedure has been validated by means of experiments performed in the cavitation tunnel K27 of the Technical University Berlin with both, the flexible and the rigid propeller. The predicted performance coefficients and the axial deformation of the blades agree well with measured values. This suggests the feasibility of using the passive bending and twisting behaviour of a flexible propeller to adapt the pressure distribution on the blade to improve the propeller performance over a range of advance ratios.
{"title":"Numerical and experimental fluid–structure interaction analysis of a flexible propeller","authors":"D. Fuentes, A. Cura Hochbaum, R. Schulze","doi":"10.1080/09377255.2022.2115241","DOIUrl":"https://doi.org/10.1080/09377255.2022.2115241","url":null,"abstract":"ABSTRACT The increasing interest in using flexible materials to design marine propellers, considering deformations due to flow loads. A numerical procedure for analysing two-way fluid-structure interactions, based on the commercial STAR-CCM+ multiphysics software, is described and applied to predict the hydroelastic response of the flexible marine propeller P1790 to hydrodynamic forces in open water conditions. The influence of the deformation on the performance of the flexible propeller was analysed by comparison with its rigid counterpart. The procedure has been validated by means of experiments performed in the cavitation tunnel K27 of the Technical University Berlin with both, the flexible and the rigid propeller. The predicted performance coefficients and the axial deformation of the blades agree well with measured values. This suggests the feasibility of using the passive bending and twisting behaviour of a flexible propeller to adapt the pressure distribution on the blade to improve the propeller performance over a range of advance ratios.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"70 1","pages":"163 - 173"},"PeriodicalIF":2.2,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47782011","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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