内孤立波广泛存在于实际海洋中,由于其诱导的水平流速大,对海洋结构物水动力性能的影响不可忽视.近年来,针对内孤立波对浮式海洋结构物作用的载荷理论逐步完善,但对于内孤立波与潜体的作用特性有待进一步研究.文中将Morison公式和Froude...内孤立波广泛存在于实际海洋中,由于其诱导的水平流速大,对海洋结构物水动力性能的影响不可忽视.近年来,针对内孤立波对浮式海洋结构物作用的载荷理论逐步完善,但对于内孤立波与潜体的作用特性有待进一步研究.文中将Morison公式和Froude-Krylov公式相结合,建立了内孤立波作用下水下潜体载荷的一种简化理论模型.基于流体体积(volume of fluid,VOF)方法,结合3类内孤立波理论模型,设计速度入口函数,开展内孤立波与水下潜体相互作用数值模拟研究,结合文献中的模型实验结果,对数值模拟方法的可靠性进行了验证.通过系列CFD模拟,结合水下潜体内孤立波载荷简化理论模型,获得了内孤立波作用下潜体模型拖曳力及惯性力系数的拟合公式.该简化理论模型对研究内孤立波作用下水下潜体的载荷特性具有一定的参考价值.展开更多
This paper investigates mathematical modelling of response amplitude operator （RAO） or transfer function using the frequency-based analysis for uncoupled roll motion of a floating body under the influence of small a...This paper investigates mathematical modelling of response amplitude operator （RAO） or transfer function using the frequency-based analysis for uncoupled roll motion of a floating body under the influence of small amplitude regular waves. The hydrodynamic coefficients are computed using strip theory formulation by integrating over the length of the floating body. Considering sinusoidal wave with frequency （ω ） varying between 0.3 rad/s and 1.2 rad/s acts on beam to the floating body for zero forward speed, analytical expressions of RAO in frequency domain is obtained. Using the normalization procedure and frequency based analysis, group based classifications are obtained and accordingly governing equations are formulated for each case. After applying the fourth order Runge-Kutta method numerical solutions are obtained and relative importance of the hydrodynamic coefficients is analyzed. To illustrate the roll amplitude effects numerical experiments have been carried out for a Panamax container ship under the action of sinusoidal wave with a fixed wave height. The effect of viscous damping on RAO is evaluated and the model is validated using convergence, consistency and stability analysis. This modelling approach could be useful to model floating body dynamics for higher degrees of freedom and to validate the result.展开更多
文摘内孤立波广泛存在于实际海洋中,由于其诱导的水平流速大,对海洋结构物水动力性能的影响不可忽视.近年来,针对内孤立波对浮式海洋结构物作用的载荷理论逐步完善,但对于内孤立波与潜体的作用特性有待进一步研究.文中将Morison公式和Froude-Krylov公式相结合,建立了内孤立波作用下水下潜体载荷的一种简化理论模型.基于流体体积(volume of fluid,VOF)方法,结合3类内孤立波理论模型,设计速度入口函数,开展内孤立波与水下潜体相互作用数值模拟研究,结合文献中的模型实验结果,对数值模拟方法的可靠性进行了验证.通过系列CFD模拟,结合水下潜体内孤立波载荷简化理论模型,获得了内孤立波作用下潜体模型拖曳力及惯性力系数的拟合公式.该简化理论模型对研究内孤立波作用下水下潜体的载荷特性具有一定的参考价值.
基金The financial grant of Islamic Azad University Kermanshah branch,Iran(Grant No:35/3/622281,7-9-2009)
文摘This paper investigates mathematical modelling of response amplitude operator （RAO） or transfer function using the frequency-based analysis for uncoupled roll motion of a floating body under the influence of small amplitude regular waves. The hydrodynamic coefficients are computed using strip theory formulation by integrating over the length of the floating body. Considering sinusoidal wave with frequency （ω ） varying between 0.3 rad/s and 1.2 rad/s acts on beam to the floating body for zero forward speed, analytical expressions of RAO in frequency domain is obtained. Using the normalization procedure and frequency based analysis, group based classifications are obtained and accordingly governing equations are formulated for each case. After applying the fourth order Runge-Kutta method numerical solutions are obtained and relative importance of the hydrodynamic coefficients is analyzed. To illustrate the roll amplitude effects numerical experiments have been carried out for a Panamax container ship under the action of sinusoidal wave with a fixed wave height. The effect of viscous damping on RAO is evaluated and the model is validated using convergence, consistency and stability analysis. This modelling approach could be useful to model floating body dynamics for higher degrees of freedom and to validate the result.
