北极运输船舶常航行于由破冰船开辟的碎冰航道中;尽管这避免了船舶与层冰碰撞引起的巨大冰阻力,但船舶与航道中碎冰的相互作用受到两侧层冰的影响,进而会对船舶的航行性能产生影响。目前,碎冰航道两侧层冰对船舶航行性能的影响尚未得到...北极运输船舶常航行于由破冰船开辟的碎冰航道中;尽管这避免了船舶与层冰碰撞引起的巨大冰阻力,但船舶与航道中碎冰的相互作用受到两侧层冰的影响,进而会对船舶的航行性能产生影响。目前,碎冰航道两侧层冰对船舶航行性能的影响尚未得到充分研究,是否考虑这一影响是北极船舶设计的一个重要问题,采用CFD-DEM(computational fluid dynamics-discrete element method)耦合方法模拟船舶在碎冰航道中的航行过程并分析船-碎冰相互作用特点,进而对船舶阻力进行数值预报。首先,开展了网格和时间步长的收敛性分析以评估数值误差和不确定度,验证了数值模型的可靠性;在此基础上的预报结果表明,由于两侧层冰对船舶兴波产生影响,船舶水阻力随航道宽度的减小而小幅增大且主要为压阻力的增加;船舶冰阻力随航道宽度的减小而迅速增大,船体两侧的碎冰堆积现象是导致冰阻力增大的主要原因。展开更多
By solving the three-dimensional incompressible Reynolds-averaged Navier-Stokes equations,numerical simulations of the viscous flow within a flush type intake duct of a waterjet under different motion conditions are c...By solving the three-dimensional incompressible Reynolds-averaged Navier-Stokes equations,numerical simulations of the viscous flow within a flush type intake duct of a waterjet under different motion conditions are carried out.Therein,the effects of the steering and reversing unit as well as the impeller shaft on the flow field are taken into account.The numerical results show that the static pressure under backward conditions with the reversing jet flow is the lowest,and the cavitations are most likely to occur within the intake duct.The flow field under forward conditions is less uniform because of the shaft,while the velocity uniformity under backward conditions is improved.The shaft rotation causes an asymmetric secondary flow above the shaft under all conditions.The pressure contours under backward conditions with the reversing jet flow are sensitive to the presence of the shaft.This study can provide some references for the design optimization of waterjet propulsion system.展开更多
文摘北极运输船舶常航行于由破冰船开辟的碎冰航道中;尽管这避免了船舶与层冰碰撞引起的巨大冰阻力,但船舶与航道中碎冰的相互作用受到两侧层冰的影响,进而会对船舶的航行性能产生影响。目前,碎冰航道两侧层冰对船舶航行性能的影响尚未得到充分研究,是否考虑这一影响是北极船舶设计的一个重要问题,采用CFD-DEM(computational fluid dynamics-discrete element method)耦合方法模拟船舶在碎冰航道中的航行过程并分析船-碎冰相互作用特点,进而对船舶阻力进行数值预报。首先,开展了网格和时间步长的收敛性分析以评估数值误差和不确定度,验证了数值模型的可靠性;在此基础上的预报结果表明,由于两侧层冰对船舶兴波产生影响,船舶水阻力随航道宽度的减小而小幅增大且主要为压阻力的增加;船舶冰阻力随航道宽度的减小而迅速增大,船体两侧的碎冰堆积现象是导致冰阻力增大的主要原因。
基金the Fund of Key Laboratory of Waterjet Propulsion Technology of MARIC(No.61422230301162223010)。
文摘By solving the three-dimensional incompressible Reynolds-averaged Navier-Stokes equations,numerical simulations of the viscous flow within a flush type intake duct of a waterjet under different motion conditions are carried out.Therein,the effects of the steering and reversing unit as well as the impeller shaft on the flow field are taken into account.The numerical results show that the static pressure under backward conditions with the reversing jet flow is the lowest,and the cavitations are most likely to occur within the intake duct.The flow field under forward conditions is less uniform because of the shaft,while the velocity uniformity under backward conditions is improved.The shaft rotation causes an asymmetric secondary flow above the shaft under all conditions.The pressure contours under backward conditions with the reversing jet flow are sensitive to the presence of the shaft.This study can provide some references for the design optimization of waterjet propulsion system.
