Large size vessels sailing in continuous level ice and broken ice of high concentration are mostly assisted by icebreakers.This is done in order to provide for fast transportation through the North Sea Route and safe ...Large size vessels sailing in continuous level ice and broken ice of high concentration are mostly assisted by icebreakers.This is done in order to provide for fast transportation through the North Sea Route and safe operation in extreme ice conditions.Currently,new large size gas and oil carriers and container ships are being designed and built with beams much greater than the beams of existing icebreakers.At the same time,no mathematical description exists for the breaking mechanism of ice channel edges,when such vessels move under icebreaker escort.This paper suggests a simple method for assessment of the ice resistance in the case of a large ship running in an icebreaker channel;the method is based on modification of well-known semi-empirical methods for calculation of the ice resistance to ships in level and broken ice.The main feature of the proposed calculation scheme consists in that different methods are applied to estimate the ice resistance in broken ice and due to breaking of level ice edges.The combination of these methods gives a deliverable ice resistance of a large size vessel moving under icebreaker assistance in a newly made ice channel.In general,proposed method allows to define the speed of a carrier moving in an ice channel behind a modern linear icebreaker and could be applied at the ship design stage and during development of the marine transportation system.The paper also discusses the ways for further refinement of the assessment procedure suggested.展开更多
The demand for high-speed boats that operating near to shoreline is increasing nowadays.Understanding the behavior and attitude of high-speed boats when moving in different waterways is very important for boat designe...The demand for high-speed boats that operating near to shoreline is increasing nowadays.Understanding the behavior and attitude of high-speed boats when moving in different waterways is very important for boat designer.This research uses a CFD(Computational Fluid Dynamics)analysis to investigate the shallow water effects on prismatic planing hull.The turbulence fl ow around the hull was described by Reynolds Navier Stokes equations RANSE using the k-ɛturbulence model.The free surface was modelled by the volume of fl uid(VOF)method.The analysis is steady for all the ranges of speeds except those close to the critical speed range Fh=0.84 to 1.27 due to the propagation of the planing hull solitary waves at this range.In this study,the planing hull lift force,total resistance,and wave pattern for the range of subcritical speeds,critical speeds,and supercritical speeds have been calculated using CFD.The numerical results have been compared with experimental results.The dynamic pressure distribution on the planing hull and its wave pattern at critical speed in shallow water were compared with those in deep water.The numerical results give a good agreement with the experimental results whereas total average error equals 7%for numerical lift force,and 8%for numerical total resistance.The worst effect on the planing hull in shallow channels occurs at the critical speed range,where solitary wave formulates.展开更多
基金This work was funded by the Russian Science Foundation(Grant No.17-79-20162-П).
文摘Large size vessels sailing in continuous level ice and broken ice of high concentration are mostly assisted by icebreakers.This is done in order to provide for fast transportation through the North Sea Route and safe operation in extreme ice conditions.Currently,new large size gas and oil carriers and container ships are being designed and built with beams much greater than the beams of existing icebreakers.At the same time,no mathematical description exists for the breaking mechanism of ice channel edges,when such vessels move under icebreaker escort.This paper suggests a simple method for assessment of the ice resistance in the case of a large ship running in an icebreaker channel;the method is based on modification of well-known semi-empirical methods for calculation of the ice resistance to ships in level and broken ice.The main feature of the proposed calculation scheme consists in that different methods are applied to estimate the ice resistance in broken ice and due to breaking of level ice edges.The combination of these methods gives a deliverable ice resistance of a large size vessel moving under icebreaker assistance in a newly made ice channel.In general,proposed method allows to define the speed of a carrier moving in an ice channel behind a modern linear icebreaker and could be applied at the ship design stage and during development of the marine transportation system.The paper also discusses the ways for further refinement of the assessment procedure suggested.
文摘The demand for high-speed boats that operating near to shoreline is increasing nowadays.Understanding the behavior and attitude of high-speed boats when moving in different waterways is very important for boat designer.This research uses a CFD(Computational Fluid Dynamics)analysis to investigate the shallow water effects on prismatic planing hull.The turbulence fl ow around the hull was described by Reynolds Navier Stokes equations RANSE using the k-ɛturbulence model.The free surface was modelled by the volume of fl uid(VOF)method.The analysis is steady for all the ranges of speeds except those close to the critical speed range Fh=0.84 to 1.27 due to the propagation of the planing hull solitary waves at this range.In this study,the planing hull lift force,total resistance,and wave pattern for the range of subcritical speeds,critical speeds,and supercritical speeds have been calculated using CFD.The numerical results have been compared with experimental results.The dynamic pressure distribution on the planing hull and its wave pattern at critical speed in shallow water were compared with those in deep water.The numerical results give a good agreement with the experimental results whereas total average error equals 7%for numerical lift force,and 8%for numerical total resistance.The worst effect on the planing hull in shallow channels occurs at the critical speed range,where solitary wave formulates.
基金Supported by the Special Research Program of Ministry of Industry and Information Technology of China(Grant No.JCKY2016604B001)the National Science and Technology Major Project(Grant No.2016ZX05058-004-002)+1 种基金the National Natural Science Foundation of China(Grant No.51509184)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51621092)
