规则波浪中舰船摇荡耦合切片计算方法
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摘要
[目的]切片理论方法在舰船耐波性设计中有着广泛的工程应用,该方法是针对切片平均位置来计算水动力,本质上缺少船体垂荡、纵摇与横摇的运动耦合性。为有效耦合船体垂荡、纵摇与横摇的运动,[方法]基于广义纵倾角和广义吃水增量的参数,以及船体坐标系下瞬时波面方程的解析表达式,以满足波面处压力为零的条件修正波面下压力分布的计算公式(史密斯效应);基于波面方程和压力分布修正公式,给出瞬时波面下船体切片的静水力与傅汝德—克雷洛夫波浪扰动力之和的计算方法,惯性水动力和阻尼力则采用经验公式估算。建立船体垂荡、纵摇与横摇耦合的时变系数动力学方程,采用AutoCAD图形面域技术开发计算软件,数值计算规则波浪中舰船的耦合摇荡运动。[结果]数值计算结果表明,大波高时横摇幅频曲线呈现出较为显著的因摇荡耦合导致的非线性效应,同时在横摇共振区内有明显的波浪传播方向的横摇偏摇现象。[结论]所得计算方法对于舰船高海况下的耐波性预报将产生积极的作用,计算软件可以作为耐波性设计选型的评估手段。
[Objectives]The strip method is widely used in the sea-keeping design of ships, but thehydrodynamics are only evaluated for the mean-hull position,so heaving,pitching and rolling motions arenot essentially coupled. [Methods]For the effective coupling of hull heaving,pitching and rollingmotions,based on the extensive pitch angle and increased draught,and the analytical expression of theinstantaneous wave surface equation under the hull coordinate system,the calculation formula of pressuredistribution under the wave surface is amended under the condition that the pressure at the wave surface iszero(Smith effect). Based on the wave surface equation and pressure distribution correction formula,thecalculation method for obtaining the hydrostatic force on hull sections under an instantaneous wave surfaceand Froude-Krylov wave excitation force is given. Inertial hydrodynamic force and damping force arecalculated by empirical formulations. As such,the heaving,pitching and rolling coupling dynamicequations are derived via the time variants of the coefficients,and calculation software is developed on thebasis of surface area computing technology of AutoCAD.[Results]The simulation results show very clearcharacters with the linear method on small wave height,the rolling amplitude frequency response veryevidently shows non-linear effects for heavy seas,and the rolling-yawing can also be seen in the wavedirection in the resonance region.[Conclusions]This approach can be useful for predicting sea-keepingperformance in heavy seas,and the developed software may be used for evaluating sea-keeping hull forms.
[Objectives]The strip method is widely used in the sea-keeping design of ships, but thehydrodynamics are only evaluated for the mean-hull position,so heaving,pitching and rolling motions arenot essentially coupled. [Methods]For the effective coupling of hull heaving,pitching and rollingmotions,based on the extensive pitch angle and increased draught,and the analytical expression of theinstantaneous wave surface equation under the hull coordinate system,the calculation formula of pressuredistribution under the wave surface is amended under the condition that the pressure at the wave surface iszero(Smith effect). Based on the wave surface equation and pressure distribution correction formula,thecalculation method for obtaining the hydrostatic force on hull sections under an instantaneous wave surfaceand Froude-Krylov wave excitation force is given. Inertial hydrodynamic force and damping force arecalculated by empirical formulations. As such,the heaving,pitching and rolling coupling dynamicequations are derived via the time variants of the coefficients,and calculation software is developed on thebasis of surface area computing technology of AutoCAD.[Results]The simulation results show very clearcharacters with the linear method on small wave height,the rolling amplitude frequency response veryevidently shows non-linear effects for heavy seas,and the rolling-yawing can also be seen in the wavedirection in the resonance region.[Conclusions]This approach can be useful for predicting sea-keepingperformance in heavy seas,and the developed software may be used for evaluating sea-keeping hull forms.
引文
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[5]TIMMAN R,NEWMAN J N.The coupled damping coefficients of symmetric ship[J].Journal of Ship Research,1962,5(4):34-55.
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[7]MANSOUR A,OLIVEIRA J M.Hull bending moment due to ship bottom slamming in regular waves[J].Journal of Ship Research,1975,19(2):80-92.
[8]WATANAB I,SOARES G.Compartive study on the time-domain analysis of non-linear ship motions and loads[J].Marine Structures,1999,12(3):153-170.
[9]CONG L Z,HUANG Z J,ANDO S,et al.Time-domain analysis of ship motions and hydrodynamic pressures on a ship hull in wave[C]//2nd International Conference on Hydroelasticity in Marine Technology.Fukuoka,Japan,1998.
[10]GU X K,SHEN J W,MOAN T.Efficient and simplified time domain simulation of nonlinear responses of ships in waves[J].Journal of Ship Research,2003,47(3):262-273.
[11]林超友,高俊吉,朱军.舰船操纵运动时高频波浪力的算例[J].海军工程大学学报,2002,14(4):100-105.LIN C Y,GAO J J,ZHU J.Calculation examples of high frequency wave loads for the ship on the maneuvering motion[J].Journal of Naval University of Engineering,2002,14(4):100-105(in Chinese).
[12]朱军,庞永杰,徐玉如.规则波浪中舰船操纵运动计算[J].哈尔滨工程大学学报,2004,25(1):1-5.ZHU J,PANG Y J,XU Y R.Maneuvering prediction of a ship in regular waves[J].Journal of Harbin Engineering University,2004,25(1):1-5(in Chinese).
[13]朱军,刘瑞杰,葛义军.规则波浪中舰船纯稳性丧失计算研究[J].中国舰船研究,2017,12(3):1-6,15.ZHU J,LIU R J,GE Y J,et al.Pure loss of stability calculation of naval ship in regular waves[J].Chinese Journal of Ship Research,2017,12(3):1-6,15(in Chinese).
[14]PAULLING J R.The transverse stability of a ship in a longitudinal seaway[J].Journal of Ship Research,1961,4(4):37-49.
[15]HIMENO Y.Predictions of ship roll damping--State of the art:239[R].[S.l.]:The University of Michigan Department of Naval Architecture and Marine Engineering,1981.
[16]彭英声.舰船耐波性基础[M].北京:国防工业出版社,1989:56-60.
[2]SALVESEN N,TUCK E O,FALTINSEN O.Ship motions and sea loads[J].SNAME Trans,1970,78:250-287.
[3]NATO.Common procedures for seakeeping in the ship design process:STANAG 4154[S].[S.l.]:NATO Military Agency for Standardisation(MAS),2000.
[4]OGILVIE T F,TUCK E O.A rational strip theory for ship motions:Part I:013[R].The University of Michigan Department of Naval Architecture and Marine Engineering,1969.
[5]TIMMAN R,NEWMAN J N.The coupled damping coefficients of symmetric ship[J].Journal of Ship Research,1962,5(4):34-55.
[6]KAPLAN P,SARGENT T P.Further studies of computer simulation of slamming and other wave-induced vibratory structural loadings on ships in waves:SSC-231[R].Ship Structure Committee,1972.
[7]MANSOUR A,OLIVEIRA J M.Hull bending moment due to ship bottom slamming in regular waves[J].Journal of Ship Research,1975,19(2):80-92.
[8]WATANAB I,SOARES G.Compartive study on the time-domain analysis of non-linear ship motions and loads[J].Marine Structures,1999,12(3):153-170.
[9]CONG L Z,HUANG Z J,ANDO S,et al.Time-domain analysis of ship motions and hydrodynamic pressures on a ship hull in wave[C]//2nd International Conference on Hydroelasticity in Marine Technology.Fukuoka,Japan,1998.
[10]GU X K,SHEN J W,MOAN T.Efficient and simplified time domain simulation of nonlinear responses of ships in waves[J].Journal of Ship Research,2003,47(3):262-273.
[11]林超友,高俊吉,朱军.舰船操纵运动时高频波浪力的算例[J].海军工程大学学报,2002,14(4):100-105.LIN C Y,GAO J J,ZHU J.Calculation examples of high frequency wave loads for the ship on the maneuvering motion[J].Journal of Naval University of Engineering,2002,14(4):100-105(in Chinese).
[12]朱军,庞永杰,徐玉如.规则波浪中舰船操纵运动计算[J].哈尔滨工程大学学报,2004,25(1):1-5.ZHU J,PANG Y J,XU Y R.Maneuvering prediction of a ship in regular waves[J].Journal of Harbin Engineering University,2004,25(1):1-5(in Chinese).
[13]朱军,刘瑞杰,葛义军.规则波浪中舰船纯稳性丧失计算研究[J].中国舰船研究,2017,12(3):1-6,15.ZHU J,LIU R J,GE Y J,et al.Pure loss of stability calculation of naval ship in regular waves[J].Chinese Journal of Ship Research,2017,12(3):1-6,15(in Chinese).
[14]PAULLING J R.The transverse stability of a ship in a longitudinal seaway[J].Journal of Ship Research,1961,4(4):37-49.
[15]HIMENO Y.Predictions of ship roll damping--State of the art:239[R].[S.l.]:The University of Michigan Department of Naval Architecture and Marine Engineering,1981.
[16]彭英声.舰船耐波性基础[M].北京:国防工业出版社,1989:56-60.