In this study, the applicability of CFD to the design of the optimal arrangement of hull FIN, which is one of the energy-saving devices, was investigated. Considering the calculation environment at the design site of a shipyard, CFD with overset grid approach was applied because it is possible to maintain the accuracy for estimating the energy-saving effect with a small number of grids. The hull FIN is attached to the JBC hull form, and the effect of the installation position in the front/rear and vertical directions on the energy-saving effect was investigated. As a result, it was found that the main reason for the performance improvement by the hull FIN was the wake gain by moving the position of the stern vortex to the outer circumference of the propeller circle. From this, it was also shown that this method is effective for understanding the performance improvement mechanism of energy-saving devices.
{"title":"船体FINの船尾流れおよび性能改善に与える影響の数値解析","authors":"Satoru Ishikawa","doi":"10.2534/jjasnaoe.37.1","DOIUrl":"https://doi.org/10.2534/jjasnaoe.37.1","url":null,"abstract":"In this study, the applicability of CFD to the design of the optimal arrangement of hull FIN, which is one of the energy-saving devices, was investigated. Considering the calculation environment at the design site of a shipyard, CFD with overset grid approach was applied because it is possible to maintain the accuracy for estimating the energy-saving effect with a small number of grids. The hull FIN is attached to the JBC hull form, and the effect of the installation position in the front/rear and vertical directions on the energy-saving effect was investigated. As a result, it was found that the main reason for the performance improvement by the hull FIN was the wake gain by moving the position of the stern vortex to the outer circumference of the propeller circle. From this, it was also shown that this method is effective for understanding the performance improvement mechanism of energy-saving devices.","PeriodicalId":499055,"journal":{"name":"Nihon sempaku kaiyou kougakkai rombunshuu","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135828964","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}
A new risk assessment method for anchor dragging is proposed. Using several kinds of information that can be commonly obtained on the navigational bridge of ships, the touch down point of the anchor chain to the seabed is estimated based on the ship’s equations of motion. Firstly, accelerations and velocities of the ship are numerically evaluated using GPS data. Secondly, the hydrodynamic forces, such as added mass, damping force and wind force, are estimated based on the theory of ship maneuverability. Thirdly, the tension of the anchor chain is determined as a residual term of the equations of motion. Finally, the touch down point of the anchor chain to the seabed is estimated based on the catenary theory. In this study, the point is named as the Virtual Touch Down Point (VTDP) and used for estimation of the length of the anchor chain crawling on the seabed and its holding power.
{"title":"A Study on Risk Assessment for Anchor Dragging Using On-board Measurement Data of a Single Anchored Vessel","authors":"Akira Saito, Toshio Iseki, Mitsuhiro Masuda","doi":"10.2534/jjasnaoe.37.19","DOIUrl":"https://doi.org/10.2534/jjasnaoe.37.19","url":null,"abstract":"A new risk assessment method for anchor dragging is proposed. Using several kinds of information that can be commonly obtained on the navigational bridge of ships, the touch down point of the anchor chain to the seabed is estimated based on the ship’s equations of motion. Firstly, accelerations and velocities of the ship are numerically evaluated using GPS data. Secondly, the hydrodynamic forces, such as added mass, damping force and wind force, are estimated based on the theory of ship maneuverability. Thirdly, the tension of the anchor chain is determined as a residual term of the equations of motion. Finally, the touch down point of the anchor chain to the seabed is estimated based on the catenary theory. In this study, the point is named as the Virtual Touch Down Point (VTDP) and used for estimation of the length of the anchor chain crawling on the seabed and its holding power.","PeriodicalId":499055,"journal":{"name":"Nihon sempaku kaiyou kougakkai rombunshuu","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135828966","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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