Pub Date : 2020-10-07DOI: 10.1080/09377255.2020.1836552
Angus Gray-Stephens, T. Tezdogan, S. Day
ABSTRACT This study details an extensive investigation into the nearfield longitudinal wake profiles of a high-speed planing hull. Developing understanding this flow is benaficial to the designers of stepped hulls in determining how the forebody’s wake intersects with the afterbody. As no experimental data was available, a novel small-scale model-testing programme was undertaken, measuring Centreline (CL) and Quarter Beam (QB) nearfield longitudinal wake profiles, as well as the forces. The nearfield wake profile was found to exhibit trends in agreement with the findings of studies investigating the mid and far-field wake. The results of this experimental work are provided in full as validation data. Savitsky’s Wake Equations and the Linear Wake Assumption are then assessed to determine the level of confidence with which they may be used to model this flow. Savitsky’s Wake Equations displayed a surprising level of accuracy whereas the Linear Wake Assumption was invalid for the conditions investigated.
{"title":"Experimental measurement of the nearfield longitudinal wake profiles of a high-speed prismatic planing hull","authors":"Angus Gray-Stephens, T. Tezdogan, S. Day","doi":"10.1080/09377255.2020.1836552","DOIUrl":"https://doi.org/10.1080/09377255.2020.1836552","url":null,"abstract":"ABSTRACT This study details an extensive investigation into the nearfield longitudinal wake profiles of a high-speed planing hull. Developing understanding this flow is benaficial to the designers of stepped hulls in determining how the forebody’s wake intersects with the afterbody. As no experimental data was available, a novel small-scale model-testing programme was undertaken, measuring Centreline (CL) and Quarter Beam (QB) nearfield longitudinal wake profiles, as well as the forces. The nearfield wake profile was found to exhibit trends in agreement with the findings of studies investigating the mid and far-field wake. The results of this experimental work are provided in full as validation data. Savitsky’s Wake Equations and the Linear Wake Assumption are then assessed to determine the level of confidence with which they may be used to model this flow. Savitsky’s Wake Equations displayed a surprising level of accuracy whereas the Linear Wake Assumption was invalid for the conditions investigated.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"68 1","pages":"102 - 128"},"PeriodicalIF":2.2,"publicationDate":"2020-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1836552","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46911815","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 : 2020-09-02DOI: 10.1080/09377255.2020.1808759
A. Betge, A. Cura Hochbaum, E. Weitendorf
ABSTRACT Cavitation test results of identical bodies obtained in different cavitation tunnels sometimes differ from each other. One main reason for this is the influence of gas and nuclei content in the water. The knowledge of the water quality in the tunnel is crucial for comparing different results and for transferring them to full scale. Holography is a very promising optical technique for the measurement of cavitation nuclei, not least because of its accuracy, reliability, and repeatability at relatively low costs for its setup. First inline holography measurements have been performed at the cavitation tunnel K27 of TU Berlin with a preliminary setup. The K27 has a free water surface and therefore a high degassing behaviour. Selected measurements have been analysed and their results are shown here. Possible improvements for the test setup are considered. An inline digital holography configuration with laser and camera inside of the test section seems promising.
{"title":"Measurement of nuclei content by digital holography in a free surface cavitation tunnel","authors":"A. Betge, A. Cura Hochbaum, E. Weitendorf","doi":"10.1080/09377255.2020.1808759","DOIUrl":"https://doi.org/10.1080/09377255.2020.1808759","url":null,"abstract":"ABSTRACT Cavitation test results of identical bodies obtained in different cavitation tunnels sometimes differ from each other. One main reason for this is the influence of gas and nuclei content in the water. The knowledge of the water quality in the tunnel is crucial for comparing different results and for transferring them to full scale. Holography is a very promising optical technique for the measurement of cavitation nuclei, not least because of its accuracy, reliability, and repeatability at relatively low costs for its setup. First inline holography measurements have been performed at the cavitation tunnel K27 of TU Berlin with a preliminary setup. The K27 has a free water surface and therefore a high degassing behaviour. Selected measurements have been analysed and their results are shown here. Possible improvements for the test setup are considered. An inline digital holography configuration with laser and camera inside of the test section seems promising.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"68 1","pages":"63 - 69"},"PeriodicalIF":2.2,"publicationDate":"2020-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1808759","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48810333","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 : 2020-08-06DOI: 10.1080/09377255.2020.1802165
Malte Mittendorf, A. Papanikolaou
ABSTRACT This paper demonstrates the practical benefit of using efficient computational methods to optimize fast catamarans hydrodynamically. The development of a simplified panel method, which is based on thin ship theory, and the validation of the associated code for the prediction of the calm water resistance of twin-hull vessels is presented. The method was applied in the multi-objective optimization of a fast, zero-emission, battery-driven catamaran by a genetic algorithm, while considering the ensuing design constraints. Results of the study were compared with resistance predictions from a non-linear Rankine panel method and a viscous CFD solver. Moreover, surrogate models were implemented to speed up the optimization process involving several hundred parametrically generated designs. The proposed simplified panel method in connection with a empirical correction for the stern flow proved very valuable in the resistance prediction and hull form optimization of fast catamarans and of slender hulls in general.
{"title":"Hydrodynamic hull form optimization of fast catamarans using surrogate models","authors":"Malte Mittendorf, A. Papanikolaou","doi":"10.1080/09377255.2020.1802165","DOIUrl":"https://doi.org/10.1080/09377255.2020.1802165","url":null,"abstract":"ABSTRACT This paper demonstrates the practical benefit of using efficient computational methods to optimize fast catamarans hydrodynamically. The development of a simplified panel method, which is based on thin ship theory, and the validation of the associated code for the prediction of the calm water resistance of twin-hull vessels is presented. The method was applied in the multi-objective optimization of a fast, zero-emission, battery-driven catamaran by a genetic algorithm, while considering the ensuing design constraints. Results of the study were compared with resistance predictions from a non-linear Rankine panel method and a viscous CFD solver. Moreover, surrogate models were implemented to speed up the optimization process involving several hundred parametrically generated designs. The proposed simplified panel method in connection with a empirical correction for the stern flow proved very valuable in the resistance prediction and hull form optimization of fast catamarans and of slender hulls in general.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"68 1","pages":"14 - 26"},"PeriodicalIF":2.2,"publicationDate":"2020-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1802165","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49595624","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 : 2020-07-27DOI: 10.1080/09377255.2020.1798060
M. Andrun, B. Blagojević, J. Bašić, B. Klarin
ABSTRACT This article discusses numerical prediction of ventilated flows around the surface-piercing hydrofoil. A ventilated cavity is developed on the hydrofoil surface and the growth of the cavity is uncontrolled, which can have harmful effects as it leads to changes in the lift and unexpected loads. The occurrence of ventilation is computed by a Reynolds-Averaged Navier–Stokes solver based on the Finite Volume Method and the Volume of Fluid free surface capturing. The impact of numerical parameters on the ventilation is investigated by testing various momentum, gradient, and interface-capturing schemes, turbulence intesities, acceleration and time stepping scenarios, for 10 Froude numbers and 2 angles of attack. The analysis shows that simulations are consistent and comparable with the experimental data, if proper free surface capturing scheme and very low Courant numbers are used.
{"title":"Impact of CFD simulation parameters in prediction of ventilated flow on a surface-piercing hydrofoil","authors":"M. Andrun, B. Blagojević, J. Bašić, B. Klarin","doi":"10.1080/09377255.2020.1798060","DOIUrl":"https://doi.org/10.1080/09377255.2020.1798060","url":null,"abstract":"ABSTRACT This article discusses numerical prediction of ventilated flows around the surface-piercing hydrofoil. A ventilated cavity is developed on the hydrofoil surface and the growth of the cavity is uncontrolled, which can have harmful effects as it leads to changes in the lift and unexpected loads. The occurrence of ventilation is computed by a Reynolds-Averaged Navier–Stokes solver based on the Finite Volume Method and the Volume of Fluid free surface capturing. The impact of numerical parameters on the ventilation is investigated by testing various momentum, gradient, and interface-capturing schemes, turbulence intesities, acceleration and time stepping scenarios, for 10 Froude numbers and 2 angles of attack. The analysis shows that simulations are consistent and comparable with the experimental data, if proper free surface capturing scheme and very low Courant numbers are used.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"68 1","pages":"1 - 13"},"PeriodicalIF":2.2,"publicationDate":"2020-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1798060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49630336","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 : 2020-07-07DOI: 10.1080/09377255.2020.1786932
A. Bambulyak, S. Ehlers
ABSTRACT The global demand in energy resources is moving the petroleum industry to the Arctic with its huge resource potential. The lack of infrastructure onshore increases the role of the Arctic marine shipping and the importance of the Northern Sea Route (NSR). Shipping within NSR waters is associated with challenges and risks, including environmental ones, and may lead to high losses caused by an accidental oil spill. The present paper provides a description and the results from the application of a simulation model for selected tanker collision scenarios with an evaluation of possible oil spill sizes as result of discharge time, penetration depth, energy and force applied. NSR navigation data from 2013, the year with the record number of transits through NSR, were studied. These were used to generate probable oil spill scenarios caused by tanker collision, and financial liabilities for environmental damage were calculated using existing international and Russian methods.
{"title":"Oil spill damage: a collision scenario and financial liability estimations for the Northern Sea Route area","authors":"A. Bambulyak, S. Ehlers","doi":"10.1080/09377255.2020.1786932","DOIUrl":"https://doi.org/10.1080/09377255.2020.1786932","url":null,"abstract":"ABSTRACT The global demand in energy resources is moving the petroleum industry to the Arctic with its huge resource potential. The lack of infrastructure onshore increases the role of the Arctic marine shipping and the importance of the Northern Sea Route (NSR). Shipping within NSR waters is associated with challenges and risks, including environmental ones, and may lead to high losses caused by an accidental oil spill. The present paper provides a description and the results from the application of a simulation model for selected tanker collision scenarios with an evaluation of possible oil spill sizes as result of discharge time, penetration depth, energy and force applied. NSR navigation data from 2013, the year with the record number of transits through NSR, were studied. These were used to generate probable oil spill scenarios caused by tanker collision, and financial liabilities for environmental damage were calculated using existing international and Russian methods.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"148 - 164"},"PeriodicalIF":2.2,"publicationDate":"2020-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1786932","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48326100","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 : 2020-06-16DOI: 10.1080/09377255.2020.1780717
Shukui Liu
ABSTRACT This study reviews alternative analytical methods accounting for the influence of ship’s finite draft on the drift force due to diffraction effect. In very short waves, the wave is completed reflected and no wave energy can be transmitted under the ship. As the wave becomes longer, however, only part of the wave will be reflected and the remainder transmitted. The reflected waves will induce drift force due to its interaction with the ship between free surface and draft. The former effect can be quantified by the reflection coefficient, while the latter can be account for by introducing the draft based exponential function ( ). When both effects are accounted for, a unified and theoretically more complete formulation results. The performance of the method is demonstrated by comparative results for a vertical plate of finite draft and a standard ship.
{"title":"Revisiting the influence of a ship’s draft on the drift force due to diffraction effect","authors":"Shukui Liu","doi":"10.1080/09377255.2020.1780717","DOIUrl":"https://doi.org/10.1080/09377255.2020.1780717","url":null,"abstract":"ABSTRACT This study reviews alternative analytical methods accounting for the influence of ship’s finite draft on the drift force due to diffraction effect. In very short waves, the wave is completed reflected and no wave energy can be transmitted under the ship. As the wave becomes longer, however, only part of the wave will be reflected and the remainder transmitted. The reflected waves will induce drift force due to its interaction with the ship between free surface and draft. The former effect can be quantified by the reflection coefficient, while the latter can be account for by introducing the draft based exponential function ( ). When both effects are accounted for, a unified and theoretically more complete formulation results. The performance of the method is demonstrated by comparative results for a vertical plate of finite draft and a standard ship.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"175 - 180"},"PeriodicalIF":2.2,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1780717","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48663335","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 : 2020-06-12DOI: 10.1080/09377255.2020.1759849
H. Yasukawa, Tsujimoto Masaru
ABSTRACT Resistance tests were conducted in regular and irregular head waves to study the impact of the bow shape on the added resistance of a full hull ship with block coefficient . The study used three different ship models with identical stern forms but systematically altered bow shapes. It was observed that a vertical stem without a protruding bow could help in reducing the added resistance in waves. The reduction ratio was about under both full and ballast loading conditions compared to a normal stem with a protruding bow. The strip method, known as the NMRI method, is applied in addition to the above- mentioned tests to predict the added resistances affecting the ships in regular waves and to clarify the effectiveness and range of application of the method. The NMRI method can qualitatively capture the differences in the added resistances in the bow shape series for a full hull ship. However, the calculations become less accurate under ballast loading condition.
{"title":"Impact of bow shape on added resistance of a full hull ship in head waves","authors":"H. Yasukawa, Tsujimoto Masaru","doi":"10.1080/09377255.2020.1759849","DOIUrl":"https://doi.org/10.1080/09377255.2020.1759849","url":null,"abstract":"ABSTRACT Resistance tests were conducted in regular and irregular head waves to study the impact of the bow shape on the added resistance of a full hull ship with block coefficient . The study used three different ship models with identical stern forms but systematically altered bow shapes. It was observed that a vertical stem without a protruding bow could help in reducing the added resistance in waves. The reduction ratio was about under both full and ballast loading conditions compared to a normal stem with a protruding bow. The strip method, known as the NMRI method, is applied in addition to the above- mentioned tests to predict the added resistances affecting the ships in regular waves and to clarify the effectiveness and range of application of the method. The NMRI method can qualitatively capture the differences in the added resistances in the bow shape series for a full hull ship. However, the calculations become less accurate under ballast loading condition.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"136 - 147"},"PeriodicalIF":2.2,"publicationDate":"2020-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1759849","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43732529","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 : 2020-05-18DOI: 10.1080/09377255.2020.1763591
Ali Ghasemi Koohi Kheili, A. Aghakouchak
ABSTRACT Fixed offshore platforms are always subjected to dynamic loading. A potentially economical method to improve the dynamic behaviour of these platforms is using passive control devices. In this paper, the application of tuned liquid damper, TLD, in controlling the response of a fixed offshore platform located in the Persian Gulf against earthquake and wave loading was studied. Analysis of a 3D model of the structure equipped with TLDs was carried out using the finite element method, and the efficiency of TLDs was investigated. Also, the equivalent models of TLDs were constructed based on the lumped mass method, and linear wave theory and the results were compared to finite element modelling of TLD. Results showed good agreement between the finite element model of TLD and equivalent lumped mass model. Results also indicated that adding TLDs can mitigate jacket deck vibrations and their efficiency increases as wave height or ground motion increase.
{"title":"Feasibility of reducing dynamic response of a fixed offshore platform using tuned liquid dampers","authors":"Ali Ghasemi Koohi Kheili, A. Aghakouchak","doi":"10.1080/09377255.2020.1763591","DOIUrl":"https://doi.org/10.1080/09377255.2020.1763591","url":null,"abstract":"ABSTRACT Fixed offshore platforms are always subjected to dynamic loading. A potentially economical method to improve the dynamic behaviour of these platforms is using passive control devices. In this paper, the application of tuned liquid damper, TLD, in controlling the response of a fixed offshore platform located in the Persian Gulf against earthquake and wave loading was studied. Analysis of a 3D model of the structure equipped with TLDs was carried out using the finite element method, and the efficiency of TLDs was investigated. Also, the equivalent models of TLDs were constructed based on the lumped mass method, and linear wave theory and the results were compared to finite element modelling of TLD. Results showed good agreement between the finite element model of TLD and equivalent lumped mass model. Results also indicated that adding TLDs can mitigate jacket deck vibrations and their efficiency increases as wave height or ground motion increase.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"165 - 174"},"PeriodicalIF":2.2,"publicationDate":"2020-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1763591","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45822710","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 : 2020-05-13DOI: 10.1080/09377255.2020.1761618
H. Söding
ABSTRACT Accurate predictions of ship motions and loads in a steep seaway require to include contributions depending non-linearly on wave amplitude. CFD methods do that routinely, but they require very high computing effort. Previous potential methods neglect either all or at least some nonlinear effects. The present method includes all substantial nonlinear effects amenable to potential flow. Using approximations for effects of flow separation at the aft end of hull and rudder, an accuracy comparable to that of good model experiments and CFD calculations is attained. That is demonstrated for motions and loads in cross sections of a containership sailing in head and quartering waves of large amplitude. Compared are results of model experiments, CFD calculations, a linear and the new nonlinear potential flow method. Another comparison is made for motions and added resistance of a second containership in head waves, where, apparently, an exceptional accuracy of experiments and calculations has been attained. A number of new ideas which were necessary to obtain a robust and accurate, fully nonlinear procedure are described. In typical cases, the method may take only one or a few percent of the computing effort of a comparable CFD computation.
{"title":"Fast accurate seakeeping predictions","authors":"H. Söding","doi":"10.1080/09377255.2020.1761618","DOIUrl":"https://doi.org/10.1080/09377255.2020.1761618","url":null,"abstract":"ABSTRACT Accurate predictions of ship motions and loads in a steep seaway require to include contributions depending non-linearly on wave amplitude. CFD methods do that routinely, but they require very high computing effort. Previous potential methods neglect either all or at least some nonlinear effects. The present method includes all substantial nonlinear effects amenable to potential flow. Using approximations for effects of flow separation at the aft end of hull and rudder, an accuracy comparable to that of good model experiments and CFD calculations is attained. That is demonstrated for motions and loads in cross sections of a containership sailing in head and quartering waves of large amplitude. Compared are results of model experiments, CFD calculations, a linear and the new nonlinear potential flow method. Another comparison is made for motions and added resistance of a second containership in head waves, where, apparently, an exceptional accuracy of experiments and calculations has been attained. A number of new ideas which were necessary to obtain a robust and accurate, fully nonlinear procedure are described. In typical cases, the method may take only one or a few percent of the computing effort of a comparable CFD computation.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"121 - 135"},"PeriodicalIF":2.2,"publicationDate":"2020-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2020.1761618","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44256877","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 : 2020-05-03DOI: 10.1080/09377255.2019.1655260
Aleksandar-Saša Milaković, Fang Li, R. U. F. von Bock und Polach, S. Ehlers
ABSTRACT Several definitions of equivalent ice thickness for simplification of complex ice cover are found in the literature. However, their systematic analysis is currently absent. Therefore, this paper reviews different definitions and validates them against a high-fidelity ice transit simulator, determining the most accurate one, with an average error of 16% for one analysed ship, and 10.5% for the other. Furthermore, capability of equivalent ice thickness to predict ship besetting in ice is tested, accurately predicting this event in 88% of the cases. Moreover, sensitivity analysis to the parameters not included in the traditional definitions is conducted, and it is found that only the thickness of ridge consolidated layer has significant impact. Finally, traditional concept based on equivalent ice volume is extended, and a concept of equivalent-performance ice thickness is developed, outperforming the traditional approach by reducing the average error to 4.6% for one ship, and to 3.2% for the other.
{"title":"Equivalent ice thickness in ship ice transit simulations: overview of existing definitions and proposition of an improved one","authors":"Aleksandar-Saša Milaković, Fang Li, R. U. F. von Bock und Polach, S. Ehlers","doi":"10.1080/09377255.2019.1655260","DOIUrl":"https://doi.org/10.1080/09377255.2019.1655260","url":null,"abstract":"ABSTRACT Several definitions of equivalent ice thickness for simplification of complex ice cover are found in the literature. However, their systematic analysis is currently absent. Therefore, this paper reviews different definitions and validates them against a high-fidelity ice transit simulator, determining the most accurate one, with an average error of 16% for one analysed ship, and 10.5% for the other. Furthermore, capability of equivalent ice thickness to predict ship besetting in ice is tested, accurately predicting this event in 88% of the cases. Moreover, sensitivity analysis to the parameters not included in the traditional definitions is conducted, and it is found that only the thickness of ridge consolidated layer has significant impact. Finally, traditional concept based on equivalent ice volume is extended, and a concept of equivalent-performance ice thickness is developed, outperforming the traditional approach by reducing the average error to 4.6% for one ship, and to 3.2% for the other.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":"67 1","pages":"100 - 84"},"PeriodicalIF":2.2,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2019.1655260","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43110423","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：