Pub Date : 2009-10-01DOI: 10.3182/20080706-5-KR-1001.02540
L. Pivano, T. Johansen, y³vind N Smogeli
In this paper a nonlinear thrust controller for fixed pitch marine propellers with torque loss estimation and an antispin strategy is presented. The controller, designed to operate in the four-quadrant plane composed by the shaft speed and the vessel speed, is a combination of a thrust controller developed for calm/moderate sea states and an anti-spin strategy to reduce power peaks and wear-and-tear in extreme sea conditions. The thrust controller aims at producing the demanded thrust independently from the propeller losses. The anti-spin algorithm lowers the shaft speed once large torque losses are detected and increases the shaft speed to normal when the loss situation is considered over. The torque losses are estimated with a nonlinear observer. The performance of the proposed controller is validated by experiments carried out in a towing tank.
{"title":"A four-quadrant thrust controller for marine propellers with loss estimation and anti-spin : theory and experiments","authors":"L. Pivano, T. Johansen, y³vind N Smogeli","doi":"10.3182/20080706-5-KR-1001.02540","DOIUrl":"https://doi.org/10.3182/20080706-5-KR-1001.02540","url":null,"abstract":"In this paper a nonlinear thrust controller for fixed pitch marine propellers with torque loss estimation and an antispin strategy is presented. The controller, designed to operate in the four-quadrant plane composed by the shaft speed and the vessel speed, is a combination of a thrust controller developed for calm/moderate sea states and an anti-spin strategy to reduce power peaks and wear-and-tear in extreme sea conditions. The thrust controller aims at producing the demanded thrust independently from the propeller losses. The anti-spin algorithm lowers the shaft speed once large torque losses are detected and increases the shaft speed to normal when the loss situation is considered over. The torque losses are estimated with a nonlinear observer. The performance of the proposed controller is validated by experiments carried out in a towing tank.","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"50 1","pages":"229-242"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73756850","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 : 2009-07-01DOI: 10.5957/MTSN.2009.46.3.174
J. Paik, Jin Young Kim, Min Soo Kim
{"title":"Ultimate limit state performance of 170k bulk carrier structures : pre-CSR versus CSR designs","authors":"J. Paik, Jin Young Kim, Min Soo Kim","doi":"10.5957/MTSN.2009.46.3.174","DOIUrl":"https://doi.org/10.5957/MTSN.2009.46.3.174","url":null,"abstract":"","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"12 1","pages":"174-182"},"PeriodicalIF":0.0,"publicationDate":"2009-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84298642","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 : 2009-07-01DOI: 10.5957/MTSN.2009.46.3.140
D. Molyneux, Jie Xu, N. Bose
This paper presents the results of experiments to measure flow velocities around the hull of an escort tug model operating at a yaw angle of 45 deg using particle image velocimetry (PIV). The paper describes the setup, calibration, and operation of the PIV system and the analysis of the results, including an estimate of the experimental uncertainty. Flow vectors are given within planes normal to the direction of motion of the tug. One plane was on the upstream side of the hull, and the other plane was on the downstream side of the hull. The downstream measurements were made with and without a low aspect ratio fin, typical of many modern escort tug designs. The results showed that the fin, when fitted, created a large vortex under the hull of the tug. Smaller features of the flow, such as the separation of the flow at the upstream and downstream bilge corners were also defined. The intention of these experiments was to create a data set that can be used to validate computational fluid dynamics (CFD) predictions of flow vectors around an escort tug at a large yaw angle.
{"title":"Measurements of Flow Around an Escort Tug Model with a Yaw Angle","authors":"D. Molyneux, Jie Xu, N. Bose","doi":"10.5957/MTSN.2009.46.3.140","DOIUrl":"https://doi.org/10.5957/MTSN.2009.46.3.140","url":null,"abstract":"This paper presents the results of experiments to measure flow velocities around the hull of an escort tug model operating at a yaw angle of 45 deg using particle image velocimetry (PIV). The paper describes the setup, calibration, and operation of the PIV system and the analysis of the results, including an estimate of the experimental uncertainty. Flow vectors are given within planes normal to the direction of motion of the tug. One plane was on the upstream side of the hull, and the other plane was on the downstream side of the hull. The downstream measurements were made with and without a low aspect ratio fin, typical of many modern escort tug designs. The results showed that the fin, when fitted, created a large vortex under the hull of the tug. Smaller features of the flow, such as the separation of the flow at the upstream and downstream bilge corners were also defined. The intention of these experiments was to create a data set that can be used to validate computational fluid dynamics (CFD) predictions of flow vectors around an escort tug at a large yaw angle.","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"166 1","pages":"140-154"},"PeriodicalIF":0.0,"publicationDate":"2009-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76577700","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 : 2009-04-01DOI: 10.5957/MTSN.2009.46.2.107
M. Fang, J. Ju
{"title":"The dynamic simulations of the ship towing system in random waves","authors":"M. Fang, J. Ju","doi":"10.5957/MTSN.2009.46.2.107","DOIUrl":"https://doi.org/10.5957/MTSN.2009.46.2.107","url":null,"abstract":"","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"87 1","pages":"107-115"},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91045094","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 : 2007-07-01DOI: 10.5957/MT1.2007.44.3.139
W. Tann, H. Shaw
{"title":"Constructing web-based object-oriented design support system for collaborative ship modeling","authors":"W. Tann, H. Shaw","doi":"10.5957/MT1.2007.44.3.139","DOIUrl":"https://doi.org/10.5957/MT1.2007.44.3.139","url":null,"abstract":"","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"27 1","pages":"139-150"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84427493","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 : 2007-07-01DOI: 10.5957/MT1.2007.44.3.194
E. Mesbahi, R. Norman, M. Peng
{"title":"An intelligent simulation model for design and costing of high temperature ballast water treatment systems","authors":"E. Mesbahi, R. Norman, M. Peng","doi":"10.5957/MT1.2007.44.3.194","DOIUrl":"https://doi.org/10.5957/MT1.2007.44.3.194","url":null,"abstract":"","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"10 1","pages":"194-202"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88725590","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 : 2007-01-01DOI: 10.5957/MT1.2007.44.1.68
D. Wright, R. Dawson, C. Orano-Dawson
{"title":"Shipboard Trials of Menadione as a Ballast Water Treatment","authors":"D. Wright, R. Dawson, C. Orano-Dawson","doi":"10.5957/MT1.2007.44.1.68","DOIUrl":"https://doi.org/10.5957/MT1.2007.44.1.68","url":null,"abstract":"","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"14 1","pages":"68-76"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84860332","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 : 2005-07-01DOI: 10.5957/MT1.2005.42.3.144
P. Andersen, J. Friesch, J. J. kappel, L. Lundegaard, G. Patience
The principle of nonplanar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or winglet at the wingtip has been developed for aircraft, the application of the nonplanar principle to marine propellers, dealt with in this paper, has led to the KAPPEL propeller with blades curved toward the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental, and practical approach to develop and design marine propellers with nonplanar lifting surfaces has resulted in propellers with higher efficiency and lower levels of noise and vibration excitation compared to conventional state-of-the-art propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium-sized containership and a product tanker. In total, nine KAPPEL propellers and two conventional propellers have been designed, and models of all propellers have been examined with respect to cavitation and efficiency in the open-water and behind conditions. Casting procedures, measurement procedures, and stress analysis methods for the unconventional geometry of the KAPPEL propeller have been developed. Furthermore, the KAPPEL propeller has been applied in full scale to the product carrier investigated. Sea trials with the conventional propeller and the KAPPEL propeller have been performed and have proved an efficiency gain of 4% in favor of the new propeller. The improved efficiency was obtained at lower propeller-induced pressure fluctuations. The correlation between the theoretical, experimental, and full-scale results is discussed.
{"title":"Development of a Marine Propeller With Nonplanar Lifting Surfaces","authors":"P. Andersen, J. Friesch, J. J. kappel, L. Lundegaard, G. Patience","doi":"10.5957/MT1.2005.42.3.144","DOIUrl":"https://doi.org/10.5957/MT1.2005.42.3.144","url":null,"abstract":"The principle of nonplanar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or winglet at the wingtip has been developed for aircraft, the application of the nonplanar principle to marine propellers, dealt with in this paper, has led to the KAPPEL propeller with blades curved toward the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental, and practical approach to develop and design marine propellers with nonplanar lifting surfaces has resulted in propellers with higher efficiency and lower levels of noise and vibration excitation compared to conventional state-of-the-art propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium-sized containership and a product tanker. In total, nine KAPPEL propellers and two conventional propellers have been designed, and models of all propellers have been examined with respect to cavitation and efficiency in the open-water and behind conditions. Casting procedures, measurement procedures, and stress analysis methods for the unconventional geometry of the KAPPEL propeller have been developed. Furthermore, the KAPPEL propeller has been applied in full scale to the product carrier investigated. Sea trials with the conventional propeller and the KAPPEL propeller have been performed and have proved an efficiency gain of 4% in favor of the new propeller. The improved efficiency was obtained at lower propeller-induced pressure fluctuations. The correlation between the theoretical, experimental, and full-scale results is discussed.","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"10 1","pages":"144-158"},"PeriodicalIF":0.0,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82353964","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 : 2004-07-01DOI: 10.5957/MT1.2004.41.3.102
R. Bradshaw
The combined wear of water-lubricated bearings supporting a flexible shaft has a modal characteristic, that is, the cumulative wear can be represented by distinct patterns (modes) that increase geometrically at unique rates. The instantaneous wear rates decrease exponentially with time and approach zero asymptotically. The total load on the outboard bearings decreases and the total load on the inboard bearings increases: the redistribution of outboard and inboard loads is controlled by the shaft stiffness matrix (the reaction influence numbers). The characteristics of modal wear are examined and the changes in alignment loads are calculated, particular attention being paid to reduction-gear loads. Numerical results are displayed.
{"title":"Bearing Wear and Its Effect on Shaft Alignment","authors":"R. Bradshaw","doi":"10.5957/MT1.2004.41.3.102","DOIUrl":"https://doi.org/10.5957/MT1.2004.41.3.102","url":null,"abstract":"The combined wear of water-lubricated bearings supporting a flexible shaft has a modal characteristic, that is, the cumulative wear can be represented by distinct patterns (modes) that increase geometrically at unique rates. The instantaneous wear rates decrease exponentially with time and approach zero asymptotically. The total load on the outboard bearings decreases and the total load on the inboard bearings increases: the redistribution of outboard and inboard loads is controlled by the shaft stiffness matrix (the reaction influence numbers). The characteristics of modal wear are examined and the changes in alignment loads are calculated, particular attention being paid to reduction-gear loads. Numerical results are displayed.","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"77 1","pages":"102-107"},"PeriodicalIF":0.0,"publicationDate":"2004-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79977205","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}
Filamentous algae fouling, such as Enteromorpha clathrata, is a soft and hairylike roughness that sometimes grows even thicker than a normal boundary layer. Typically, such fouling has been treated as traditional roughness functions to yield hydrodynamic characteristics. This technique has been successfully used for a thin fouling layer. However, it may not be applicable on a thicker layer, as the present study found substantial fluid flow within the layer. For such cases, the roughness cannot be treated simply as a passive geometric variable, but its kinematics and interactions with the flow must be considered. The inner law (log law) dynamics may be abnormal to yield any meaningful roughness function if it is calculated in the traditional way as the departure of a rough-wall log law profile over a smooth-wall log law profile. In the present research, velocity measurement of the E. clathrata roughness boundary layer using pitot-static tube and laser Doppler velocimeter (LDV) were compared. Large discrepancies in the velocity profiles within and in the vicinity of the roughness layer were observed between the two methods. The pitot-static tube data showed significantly high velocities (60% to 80% of the free stream) in the inner layer as compared to a smooth wall boundary layer. This local increase in velocity is believed to be the result of elastic transfer of free-stream energy to the near-wall motions by the E. clathrata filaments. Consequently, the usual assumption of the normal pressure gradient as a negligible second-order term for a normal zero-pressure gradient boundary layer may not be valid for the present kind of roughness . The LDV velocity measurements near and within the roughness layer have large uncertainties due to interference of the probe volume by the E. clathrata filaments. Above the roughness, the pitot-static tube and LDV profiles show relatively good agreement. It is concluded that for accurate prediction of the wall shear stress with E. clathrata-type of bio-fouling roughness, the Clauser velocity loss function should include a form drag factor instead of only the viscous drag factor.
{"title":"A study of hydrodynamic characteristics of boundary layer with algae roughness","authors":"C. Subramanian, N. Shinjo, S. Gangadharan","doi":"10.1115/FEDSM2002-31071","DOIUrl":"https://doi.org/10.1115/FEDSM2002-31071","url":null,"abstract":"Filamentous algae fouling, such as Enteromorpha clathrata, is a soft and hairylike roughness that sometimes grows even thicker than a normal boundary layer. Typically, such fouling has been treated as traditional roughness functions to yield hydrodynamic characteristics. This technique has been successfully used for a thin fouling layer. However, it may not be applicable on a thicker layer, as the present study found substantial fluid flow within the layer. For such cases, the roughness cannot be treated simply as a passive geometric variable, but its kinematics and interactions with the flow must be considered. The inner law (log law) dynamics may be abnormal to yield any meaningful roughness function if it is calculated in the traditional way as the departure of a rough-wall log law profile over a smooth-wall log law profile. In the present research, velocity measurement of the E. clathrata roughness boundary layer using pitot-static tube and laser Doppler velocimeter (LDV) were compared. Large discrepancies in the velocity profiles within and in the vicinity of the roughness layer were observed between the two methods. The pitot-static tube data showed significantly high velocities (60% to 80% of the free stream) in the inner layer as compared to a smooth wall boundary layer. This local increase in velocity is believed to be the result of elastic transfer of free-stream energy to the near-wall motions by the E. clathrata filaments. Consequently, the usual assumption of the normal pressure gradient as a negligible second-order term for a normal zero-pressure gradient boundary layer may not be valid for the present kind of roughness . The LDV velocity measurements near and within the roughness layer have large uncertainties due to interference of the probe volume by the E. clathrata filaments. Above the roughness, the pitot-static tube and LDV profiles show relatively good agreement. It is concluded that for accurate prediction of the wall shear stress with E. clathrata-type of bio-fouling roughness, the Clauser velocity loss function should include a form drag factor instead of only the viscous drag factor.","PeriodicalId":49310,"journal":{"name":"Marine Technology and Sname News","volume":"1 1","pages":"60-66"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79781386","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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