Volume 7: Polar and Arctic Sciences and Technology最新文献

{"title":"Wave Propagation in Continuous Sea Ice: An Experimental Perspective","authors":"Giulio Passerotti, A. Alberello, A. Dolatshah, L. Bennetts, Otto Puolakka, Franz von Bock und Polach, Marco Klein, M. Hartmann, J. Monbaliu, A. Toffoli","doi":"10.1115/omae2020-18181","DOIUrl":"https://doi.org/10.1115/omae2020-18181","url":null,"abstract":"\u0000 Ocean waves penetrate hundreds of kilometres into the ice-covered ocean. Waves fracture the level ice into small floes, herd floes, introduce warm water and overwash the floes, accelerating ice melt and causing collisions, which concurrently erodes the floes and influences the large-scale deformation. Concomitantly, interactions between waves and the sea ice cause wave energy to reduce with distance travelled into the ice cover, attenuating wave driven effects. Here a pilot experiment in the ice tank at Aalto University (Finland) is presented to discuss how the properties of irregular small amplitude (linear) waves change as they propagate through continuous model sea ice. Irregular waves with a JONSWAP spectral shape were mechanically generated with a very low initial wave steepness to avoid ice break up and maintain a consistent continuous ice cover throughout the experiments. Observations show an exponential attenuation of wave energy with distance. High frequency components attenuated more rapidly than the low frequency counterparts, in agreement with a frequency-cubed power-law. The more effective attenuation in the high frequency range induced a substantial downshift of the spectral peak, stretching the dominant wave component as it propagates in ice.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"259 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115879537","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}

{"title":"Influence of Ice Floe Shape and Distribution on Ship Resistance","authors":"M. Cahay, Gabriel Fabiano de Lima","doi":"10.1115/omae2020-18131","DOIUrl":"https://doi.org/10.1115/omae2020-18131","url":null,"abstract":"\u0000 Many ice basin tests have been performed on ships to assess the ice resistance of the hull in an ice floe field. During these tests, many parameters are studied, the most important of them being the transit speed, the thickness and the concentration of ice. Given the cost and the time required to carry out these basin test campaigns, it is imperative to keep the number of tests to the strict minimum, whilst still making it possible to draw conclusions about the sizing of the vessel. Hence, the influence of ice floe shape and their distribution in the field are generally not considered.\u0000 A way to achieve sensitivity studies regarding these parameters is to use numerical simulations in addition to a basin test. There are few advanced numerical design tools available in the market, especially those able to cope with any kind of structure geometry and a large variety of ice interaction & failure mechanisms. In 2012 TechnipFMC, Cervval and Bureau Veritas initiated a common development program to offer a new tool for the design of offshore structures interacting with ice combining a variety of models and approaches such as analytical, numerical and empirical. This numerical tool called Ice-MAS (www.ice-mas.com) uses a multi-agent technology and has the possibility to combine, in a common framework, multiple phenomena from various natures and heterogeneous scales (i.e. drag, friction, ice-sheet bending failure, local crushing and rubble stack up).\u0000 The study presented in this paper compares the simulation results for different ice floe fields not only in terms of concentration, maximum size of floe and their distribution but also in the way to generate the ice floe and its shape.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133100903","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}

{"title":"Guidance Model Representing an Ice Field for Path-Planning in Ice Management","authors":"Jon Bjørnø, Mathias Marley, R. Skjetne","doi":"10.1115/omae2020-19117","DOIUrl":"https://doi.org/10.1115/omae2020-19117","url":null,"abstract":"\u0000 In the work presented in this paper, the problem on how to represent a simplified ice field in a guidance model, enabling path and maneuver planning for IM operation, has been studied. The use of B-splines and other basis functions are considered to represent relevant guidance information over the 2D drifting ice field. A weight value is computed and updated at locations that represents broken ice (visited by an icebreaker) versus unbroken ice. The guidance model will ensure that there is a continuous representation of the state of the ice field during the operations. The drifting behavior of the ice field is incorporated into the guidance model. The model will be updated with new (solid) ice that is formed at the beginning of the ice field, and it will continuously be updated in the path where the icebreaker moves. To simulate the maneuvers of the icebreaker, a dynamic model is used, and the ice breaking effect where the ice field is continuously broken into smaller ice floes is included in the model. This representation of an ice field can be used in a path-planning algorithm to determine the icebreaker path in a moving ice environment in order to reduce the ice field into small enough ice floes and reduce the load on the protected structure.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128837454","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}

{"title":"Methodology to Investigate the Icebreaking Process of Ships With Non-Typical Icebreaking Bow Shapes","authors":"Q. Hisette, D. Myland","doi":"10.1115/omae2020-18023","DOIUrl":"https://doi.org/10.1115/omae2020-18023","url":null,"abstract":"\u0000 For non-typical icebreaking ships the hull-ice interaction process in level ice comprises a combination of many different phenomena which is difficult to be described by existing straightforward approaches. In order to gain knowledge about the level ice resistance of such non-typical hull shapes for operation in ice, a methodology is developed and presented to identify and evaluate the level ice resistance as well as its distribution along the hull of ships with non-typical icebreaking bow shapes with high stem and/or small waterline angles. For this purpose, one ship model has been manufactured and instrumented with several multi-component load cells in the bow region of the waterline as well as with one large six-component load scale between the bow and the stern. Performing resistance model tests at several loading conditions, in model ice sheets of different thickness and at multiple speed values allows obtaining relevant information to meet the goals of the study. The paper focuses on the methodology used for the ice model tests and its analysis. Instrumentation of the model is fully described, together with an overview of the testing matrix and model test observations. Analysis procedure is described in details and applied on a representative test run of the campaign.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131279939","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}

{"title":"Case Based Scaling: Recent Developments in Ice Model Testing Technology","authors":"R. V. B. U. Polach, G. Ziemer, Marco Klein, M. Hartmann, A. Toffoli, J. Monty","doi":"10.1115/omae2020-18320","DOIUrl":"https://doi.org/10.1115/omae2020-18320","url":null,"abstract":"\u0000 Model ice testing is the state of the art validation and testing method for ships and structures interacting with ice. Its initial design objective was the prediction of resistance forces of ice breaking ships by using Froude and Cauchy similitude to account to the most significant force ratios. In the ice breaking process the forces due to downward bending are considered most significant and therewith much emphasis was spent on the correct scaling of the bending strength or flexural strength of the model ice. Recent research on the mechanical behavior of model ice shows a significantly higher compliance in downward bending than targeted when following the applied scaling laws. This can lead to scale effects in the resistance force also when testing ice breaking ships. The too compliant ice facilitates an additional ride-up of the ship onto the ice and the vertical motions manifest as additional resistance contribution. The low compliance of model ice also imposes uncertainties on wave-ice interaction tests, which gain increasing significance due to the climatic changes in Polar regions. The modeling of ice break-up due to waves, with the current standard model ice, requires much steeper waves than in full scale as the ice surface needs to experience a much higher deflection to reach the critical failure stress. A similar issue arises for vertical structures exposed to drifting ice. In full-scale a pile-up of ice around the structure is observed and in the contact area so called high-pressure zones may form. Such effects cannot be modeled with classic model ice as it easily bends downwards and produces a failure pattern and failure process very different from full-scale as well as high-pressure zones do not form which is due to the string property gradient in model ice. The mentioned three scenarios are considered being highly relevant in marine research and for the marine industry and therefore this paper introduces two new model ice types with which those scenarios can be modeled. The ‘model ice of virtual equivalent thickness’ uses a different modeling approach to reach a scaled stiffness for improved modeling of waves in ice and ships’ resistance in thicker ice. The ‘wave model ice’ is modeled by using waves in the formation process and can resemble high-pressure-zones acting on a vertical structure. Both methods are considered as an extension to the existing standard model ice for dedicated scenarios by scaling or putting emphasis on different ice properties by altering the production process. The presented approach also emphasizes case-based-scaling, which means that the scaling or the model ice type needs is defined by the modeled scenario as the standard model ice is obviously not fully capable to reflect all properties of sea ice in scale.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133199883","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}

{"title":"Extreme Value Estimation of Mooring Loads Based on Station-Keeping Trials in Ice","authors":"C. Sinsabvarodom, B. Leira, W. Chai, A. Naess","doi":"10.1115/omae2020-18172","DOIUrl":"https://doi.org/10.1115/omae2020-18172","url":null,"abstract":"\u0000 The purpose of this work is to perform an extreme value estimation of the mooring loads associated with station-keeping of a ship operating in ice. In general, the design of mooring lines is based on estimation of the extreme loading caused by environmental conditions within the relevant area. In March 2017, station-keeping trials (SKT) in drifting ice were performed as part of a project headed by Statoil in the Bay of Bothnia. The objective was to investigate the characteristics of the mooring loads for the supply vessel Magne Viking for different types of physical ice management schemes. Tor Viking was employed as an ice breaker as part of the physical ice management systems. The ice conditions (i.e. the ice drift velocity and the ice thickness) during the trials were monitored by using Ice Profiling Sensors (IPSs). Different patterns of ice-breaking manoeuvers were investigated as part of the physical ice management systems, such as square updrift, round circle, circle updrift and linear updrift pattern were studied as part of the field experiments. The peak values of the mooring loads for the supply vessel are determined by using the min peak prominence method. For the purpose of extreme value prediction, the peak over threshold method and block maxima method for a specific time window are applied to estimate the mooring loads that correspond to specific probabilities of exceedance (or equivalently: return periods). These loads can then be compared to the design loads that are being specified by relevant international standards.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134254598","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}

{"title":"Evaluation of the Ice Load Acting on an Arctic Offshore Structure With Different Ice Drifting Angle","authors":"Young-Shik Kim, Yun-Ho Kim, H. Song, Jin-ho Jang, S. Han, Joo-Sung Kim, Hyunjoe Kim, M. Cahay","doi":"10.1115/omae2020-18828","DOIUrl":"https://doi.org/10.1115/omae2020-18828","url":null,"abstract":"\u0000 In this study, an evaluation method and results for ice load acting on an Arctic offshore structure with various ice drifting angles are discussed. Korea Research Institute of Ships and Ocean Engineering (KRISO) has conducted a research project to develop a hull form design for year-round floating type offshore structures in the Arctic condition with dynamic positioning and mooring system. Six cooperating organizations participated in the project: Samsung Heavy Industry, Korean Register, Pusan National University, Korea Maritime & Ocean University, Dong-Eui University, and Inha Technical College. In the design stage of an Arctic offshore structure, ice load consideration is the key component for the safety and reliability analysis. However, there is no generally used tool for evaluation of ice load acting on an Arctic offshore structures. In this study, ice loads acting on an Arctic FPSO in managed ice conditions with various ice drifting angles are examined by experimental methodology. Dramatic mean value changes in ice load with different ice drifting angles are observed in the model test. This experimental ice load evaluation method can be applied to the other types of offshore structure which might operate in sea ice condition.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117011177","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}

{"title":"Impact of Forced Roll Motion on the Ice Resistance of Modern Icebreaking Bow Geometries","authors":"J. M. Daniel, T. Romu, R. V. B. U. Polach, M. Abdel‐Maksoud, Toni Skogström","doi":"10.1115/omae2020-19178","DOIUrl":"https://doi.org/10.1115/omae2020-19178","url":null,"abstract":"\u0000 Following the development of low friction hull coatings and azimuthing propulsion for icebreaking vessels, the development of auxiliary systems for reducing ice resistance fell from focus of research. One of these systems is comprised of active heeling tanks which induce a forced roll motion on the icebreaker. Today it is not fully understood how effective or even useful such systems would be for the icebreaking performance in combination with a modern icebreaking hull form. In this study, the impact of active heeling systems on level ice resistance is investigated by performing ice model tests with an icebreaker representing the latest design generation. The level ice thickness used in the model tests corresponds to the maximum continuous icebreaking capability of the evaluated vessel in multi-year ice conditions. Additionally, a calculation method is developed to predict the impact of forced roll motion on the ice resistance. The calculated prediction is evaluated against the model-scale data. Finally, the effectiveness of the active heeling system is evaluated from an engineering perspective: does the active heeling system reduce the power demand, or would the same result be achievable by increasing the propulsion power accordingly. It was found that the roll motion impacts the ice resistance in level ice. The main influence in this regard lies with the tank volume and metacentric height of the icebreaker. Additionally, it was observed that an optimum heel angle dependent on the ice condition can be determined which is not necessarily the highest one achievable. The case study predicts a reduced power demand for a modern icebreaker hull form in harsh ice conditions.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130777153","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}

{"title":"The Status of Arctic Offshore Pipeline Standards and Technology","authors":"M. Paulin, Jonathan Caines, A. Davis, D. Degeer, Todd G. Cowin","doi":"10.1115/omae2020-19290","DOIUrl":"https://doi.org/10.1115/omae2020-19290","url":null,"abstract":"\u0000 Offshore pipelines in an Arctic or ice-covered environment face unique challenges different from traditional subsea pipeline design. In 2018, Intecsea as lead consultancy delivered a report to the US Bureau of Safety and Environmental Enforcement (BSEE) Alaska Region which provided a comprehensive review and gap analysis of the Status of Arctic Pipeline Standards and Technology. The objective of this study was to provide BSEE with a comprehensive review and gap analysis of current offshore Arctic pipeline design standards, codes and regulations pertaining to design and development of offshore pipelines in the Arctic, and to report on the state-of-the-art and emerging technologies for offshore pipelines in Arctic applications. Project development information from nine existing offshore Arctic pipelines in the U.S., Canada, and Russia was summarized, as well as guidelines and industry best-practice for monitoring and leak detection.\u0000 This paper provides an overview of the results of this study; what offshore Arctic-specific pipeline design and construction challenges may entail, how they have been overcome in past projects, perceived gaps in regulations, and technology advancements that may help with future developments. This paper also summarizes the results of a comprehensive review and gap analysis of Arctic pipeline standards, assessment of the suitability of a single-walled versus pipe-in-pipe system for Arctic applications and presents information on some of the advancements in pipeline design, installation, operations and repair solutions that may be applicable to an Arctic environment.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132534208","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}

{"title":"Damping of Regular Waves in Model Ice","authors":"M. Hartmann, R. V. B. U. Polach, Marco Klein","doi":"10.1115/omae2020-18152","DOIUrl":"https://doi.org/10.1115/omae2020-18152","url":null,"abstract":"\u0000 Wave characteristics change significantly when the waves propagate in a solid ice field. The damping of the incident waves due to the presence of the ice sheet has a significant impact on the modification of wave propagation and dispersion.\u0000 In this study the interaction of waves with solid ice are investigated by means of model tests. The objective of the study is to measure wave and ice characteristics and analyze the data regarding wave damping and the change of wave parameters in model ice.\u0000 The experiments were performed in the ice tank of the Hamburg ship model basin (HSVA) with a set of regular waves with varying wave number and steepness. The surface elevation of the waves is recorded by acoustic and motion capturing measurement devices.\u0000 By comparing the measurements of the incident open water waves with the waves in ice, the change in terms of wave amplitude and dispersion due to the presence of ice is analyzed.\u0000 It is shown that once the waves travels through the ice the angular frequency remains unchanged while the wave amplitude exponentially decays, with an increasing decay coefficient at smaller wave length. Furthermore, the dispersion relation in ice, represented by the measured angular frequency and wave number, is consistent with the theoretical dispersion relation.","PeriodicalId":108271,"journal":{"name":"Volume 7: Polar and Arctic Sciences and Technology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125361741","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}