This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid car...This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist （1989） for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.展开更多
Ship hull form of the underwater area strongly influences the resistance of the ship. The major factor in ship resistance is skin friction resistance. Bulbous bows, polymer paint, water repellent paint （highly water-...Ship hull form of the underwater area strongly influences the resistance of the ship. The major factor in ship resistance is skin friction resistance. Bulbous bows, polymer paint, water repellent paint （highly water-repellent wall）, air injection, and specific roughness have been used by researchers as an attempt to obtain the resistance reduction and operation efficiency of ships. Micro-bubble injection is a promising technique for lowering frictional resistance. The injected air bubbles are supposed to somehow modify the energy inside the turbulent boundary layer and thereby lower the skin friction. The purpose of this study was to identify the effect of injected micro bubbles on a navy fast patrol boat （FPB） 57 m type model with the following main dimensions： L=2 450 ram, B=400 mm, and T=190 mm. The influence of the location of micro bubble injection and bubble velocity was also investigated. The ship model was pulled by an electric motor whose speed could be varied and adjusted. The ship model resistance was precisely measured by a load cell transducer. Comparison of ship resistance with and without micro-bubble injection was shown on a graph as a function of the drag coefficient and Froude number. It was shown that micro bubble injection behind the mid-ship is the best location to achieve the most effective drag reduction, and the drag reduction caused by the micro-bubbles can reach 6%-9%.展开更多
In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form opt...In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form optimization design. In the ship under the conditions of use, and to optimize the design of the hull lines with boat, minimize the ship resistance, with the final choice of ship host fuel-sipping. Our research combine the characteristics of the energy efficiency with the shipbuilding industry with the novel and innovative design pattern which will be meaningful.展开更多
In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form opt...In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form optimization design. In the ship under the conditions of use, and to optimize the design of the hull lines with boat, minimize the ship resistance, with the final choice of ship host fuel-sipping. Our research combine the characteristics of the energy efficiency with the shipbuilding industry with the novel and innovative design pattern which will be meaningful.展开更多
In order to understand the influence of bow shape on ice resistance and provide guidelines for hull line design in the early design stage,an investigation of the impact of bow shape on ice resistance for the Arctic LN...In order to understand the influence of bow shape on ice resistance and provide guidelines for hull line design in the early design stage,an investigation of the impact of bow shape on ice resistance for the Arctic LNG carriers is carried out based on semi-empirical methods.Firstly,some typical semi-empirical formulas developed for ice resistance estimation of cargo carriers in different ice conditions are summarized.Then,formulas appropriate for ice resistance estimation of Arctic LNG carriers under different ice conditions are verified according to the result comparison between semi-empirical formulas and experimental tests.The comparison result indicates that the Lindqvist formula is appropriate for ice resistance estimation in level ice conditions,Zuev and Dobrodeev formula for ice resistance estimation in broken ice conditions,and Dobrodeev formula for ice resistance estimation in brash ice conditions.After that,the parameters considered in the selected formulas are summarized,and the influence of critical parameters on ice resistance is analyzed.Some parameters describing the ship's bow shape characteristic like ship breadth,waterline angle and stem angle greatly influence the ice resistance.Ice resistance increases with both the growth of ship breadth under all ice conditions and the growth of stem angle in level ice and broken ice conditions while ice resistance decreases with the development of waterline angle under all ice conditions.Finally,the optimization of the bow shape is discussed,and an optimized bow shape with both a large waterline angle and low stem angle is proposed.The optimized bow shape can decrease ice resistance by 9.9%in the level ice condition and reduce ice resistance by 11.3%in the brash ice condition.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 51179123 and 51279131
文摘This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist （1989） for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.
基金Supported by the Directorate for Research and Community Service,University of Indonesia(RUUI Research Laboratory 2010),Jakarta,Indonesia
文摘Ship hull form of the underwater area strongly influences the resistance of the ship. The major factor in ship resistance is skin friction resistance. Bulbous bows, polymer paint, water repellent paint （highly water-repellent wall）, air injection, and specific roughness have been used by researchers as an attempt to obtain the resistance reduction and operation efficiency of ships. Micro-bubble injection is a promising technique for lowering frictional resistance. The injected air bubbles are supposed to somehow modify the energy inside the turbulent boundary layer and thereby lower the skin friction. The purpose of this study was to identify the effect of injected micro bubbles on a navy fast patrol boat （FPB） 57 m type model with the following main dimensions： L=2 450 ram, B=400 mm, and T=190 mm. The influence of the location of micro bubble injection and bubble velocity was also investigated. The ship model was pulled by an electric motor whose speed could be varied and adjusted. The ship model resistance was precisely measured by a load cell transducer. Comparison of ship resistance with and without micro-bubble injection was shown on a graph as a function of the drag coefficient and Froude number. It was shown that micro bubble injection behind the mid-ship is the best location to achieve the most effective drag reduction, and the drag reduction caused by the micro-bubbles can reach 6%-9%.
文摘In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form optimization design. In the ship under the conditions of use, and to optimize the design of the hull lines with boat, minimize the ship resistance, with the final choice of ship host fuel-sipping. Our research combine the characteristics of the energy efficiency with the shipbuilding industry with the novel and innovative design pattern which will be meaningful.
文摘In this paper, we conduct research on the definition and influence of new production of ship industry index of energy efficiency on the ship design process. Ship energy saving is the key to energy saving ship form optimization design. In the ship under the conditions of use, and to optimize the design of the hull lines with boat, minimize the ship resistance, with the final choice of ship host fuel-sipping. Our research combine the characteristics of the energy efficiency with the shipbuilding industry with the novel and innovative design pattern which will be meaningful.
文摘In order to understand the influence of bow shape on ice resistance and provide guidelines for hull line design in the early design stage,an investigation of the impact of bow shape on ice resistance for the Arctic LNG carriers is carried out based on semi-empirical methods.Firstly,some typical semi-empirical formulas developed for ice resistance estimation of cargo carriers in different ice conditions are summarized.Then,formulas appropriate for ice resistance estimation of Arctic LNG carriers under different ice conditions are verified according to the result comparison between semi-empirical formulas and experimental tests.The comparison result indicates that the Lindqvist formula is appropriate for ice resistance estimation in level ice conditions,Zuev and Dobrodeev formula for ice resistance estimation in broken ice conditions,and Dobrodeev formula for ice resistance estimation in brash ice conditions.After that,the parameters considered in the selected formulas are summarized,and the influence of critical parameters on ice resistance is analyzed.Some parameters describing the ship's bow shape characteristic like ship breadth,waterline angle and stem angle greatly influence the ice resistance.Ice resistance increases with both the growth of ship breadth under all ice conditions and the growth of stem angle in level ice and broken ice conditions while ice resistance decreases with the development of waterline angle under all ice conditions.Finally,the optimization of the bow shape is discussed,and an optimized bow shape with both a large waterline angle and low stem angle is proposed.The optimized bow shape can decrease ice resistance by 9.9%in the level ice condition and reduce ice resistance by 11.3%in the brash ice condition.
