At intensive winter navigation, the ships should separate under movement on opposite courses or make overtaking of slowly moving cargo vessels in the water areas covered with ice. Under navigation within ice channel, ...At intensive winter navigation, the ships should separate under movement on opposite courses or make overtaking of slowly moving cargo vessels in the water areas covered with ice. Under navigation within ice channel, possibilities for maneuvering are reduced; therefore, danger of collision of ships exists. The ice floes between vessels hulls and outside are the major factors defining values and direction of side force and yawing moment that arise on their hulls during divergence. Ice loads on the ship hull exceed considerably the loads caused by water flow around hull. Performed previously experiments in the ice basin have detected that besides increase of side force and yawing moment modules the change of side force directions occurs during the divergence of vessels in comparison with same maneuvering on water area without ice cover. Article contains the detailed problem definition and mathematical model of ships interaction during opposite passing by or overtaking and technical approach to computation of loads on vessels hulls. As example of strategy application, the simulation of loads on overtaking ship was performed, and main results of computations are presented. Outcomes of investigation are character of variation of side force and yawing moment during passage along overtaken ship and dependence of the peak values of additional ice resistance, side force and yawing moment on beam distance between vessels and thickness that are contained in the article.展开更多
Cargo ship sailing within the ice channel that an assisting icebreaker tracks in the compact ice cover is the usual navigation practice for difficult ice conditions in freezing seas and Arcticwater areas.When the iceb...Cargo ship sailing within the ice channel that an assisting icebreaker tracks in the compact ice cover is the usual navigation practice for difficult ice conditions in freezing seas and Arcticwater areas.When the icebreaker or an ahead vessel stops before the insuperable ice obstacle or because of engine trouble,the danger of an emergency appears,namely of collision with the icebreaker or the ahead ship,if the interval between them is not sufficient for effective braking and stopping.The paper presents the equation that describes the ship braking process within an ice channel and includes the thrust of the propeller that works under the reverse regime.The specific of this regime is the following:the ship continues the motion‘forwards’and the propeller rotates‘backwards’.An analytical method for description of the ship propeller work on the reverse regime is absent because of the detached flow on its blades.The paper describes the developed empirical method of this regime parameterization on the basis of serial models of propeller testing.The outcomes of this investigation are applied to a ship braking process simulation and the evaluation of the safe interval between the ship and the icebreaker.展开更多
文摘At intensive winter navigation, the ships should separate under movement on opposite courses or make overtaking of slowly moving cargo vessels in the water areas covered with ice. Under navigation within ice channel, possibilities for maneuvering are reduced; therefore, danger of collision of ships exists. The ice floes between vessels hulls and outside are the major factors defining values and direction of side force and yawing moment that arise on their hulls during divergence. Ice loads on the ship hull exceed considerably the loads caused by water flow around hull. Performed previously experiments in the ice basin have detected that besides increase of side force and yawing moment modules the change of side force directions occurs during the divergence of vessels in comparison with same maneuvering on water area without ice cover. Article contains the detailed problem definition and mathematical model of ships interaction during opposite passing by or overtaking and technical approach to computation of loads on vessels hulls. As example of strategy application, the simulation of loads on overtaking ship was performed, and main results of computations are presented. Outcomes of investigation are character of variation of side force and yawing moment during passage along overtaken ship and dependence of the peak values of additional ice resistance, side force and yawing moment on beam distance between vessels and thickness that are contained in the article.
基金Study was implemented within project SIMREC—‘Simulators for Improving Cross-Border Oil Spill Response in Extreme Conditions’(Grant Contact No.1804147-KS1703).
文摘Cargo ship sailing within the ice channel that an assisting icebreaker tracks in the compact ice cover is the usual navigation practice for difficult ice conditions in freezing seas and Arcticwater areas.When the icebreaker or an ahead vessel stops before the insuperable ice obstacle or because of engine trouble,the danger of an emergency appears,namely of collision with the icebreaker or the ahead ship,if the interval between them is not sufficient for effective braking and stopping.The paper presents the equation that describes the ship braking process within an ice channel and includes the thrust of the propeller that works under the reverse regime.The specific of this regime is the following:the ship continues the motion‘forwards’and the propeller rotates‘backwards’.An analytical method for description of the ship propeller work on the reverse regime is absent because of the detached flow on its blades.The paper describes the developed empirical method of this regime parameterization on the basis of serial models of propeller testing.The outcomes of this investigation are applied to a ship braking process simulation and the evaluation of the safe interval between the ship and the icebreaker.
