针对工程中关心的振荡圆柱绕流问题,采用同位网格系统中的 SIMPLE算法求解 N S方程,以及动网格技术模拟圆柱的运动边界,对均匀来流中的横向振荡圆柱绕流场进行数值模拟,计算了振荡圆柱升力系数、阻力系数随时间的变化曲线,以及不同相位...针对工程中关心的振荡圆柱绕流问题,采用同位网格系统中的 SIMPLE算法求解 N S方程,以及动网格技术模拟圆柱的运动边界,对均匀来流中的横向振荡圆柱绕流场进行数值模拟,计算了振荡圆柱升力系数、阻力系数随时间的变化曲线,以及不同相位时的流线矢量图和涡量等值线分布图。为验证模型的可靠性,对静水中的振荡圆柱流场进行模拟,与实验及数值计算结果吻合较好。展开更多
The wave force exerted on vertical piles of offshore structures is the main criterion in designing them.In structures with more than one large pile,the influence of piles on each other is one of the most important iss...The wave force exerted on vertical piles of offshore structures is the main criterion in designing them.In structures with more than one large pile,the influence of piles on each other is one of the most important issues being concerned in past researches.An efficient method for determining the interaction of piles is introduced in present research.First the wave force is calculated by the exact method using the diffraction theory,then in the finite difference numerical method the force is calculated by adding the velocity potentials of each pile and integration of pressure on their surface.The results showed that the ratio of the wave force on each of the double piles to a single pile has a damped oscillation around unity in which the amplitude of oscillation decreases with the increase in the spacing parameter.Also different wave incident directions and diffraction parameters were used and the results showed that the numerical solution has acceptable accuracy when the diffraction parameter is larger than unity.展开更多
Particle Imaging Velocimetry （PIV） is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity...Particle Imaging Velocimetry （PIV） is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity along the wake central-line and the mean vertical velocity around the trailing edge of the flexible tail can be greatly increased with the tail length. Meanwhile, the longer the flexible tail is, the larger its deformation is. In order to study the influence of flexible tail length on the wake pattern of the experimental model, the relationships between the swirling strength Aci of vortex structure near the tail end and the velocity of tail trailing edge have been revealed. Moreover, the convection tracks and the Aci of vortex cores for different flexible tails are discussed.展开更多
文摘针对工程中关心的振荡圆柱绕流问题,采用同位网格系统中的 SIMPLE算法求解 N S方程,以及动网格技术模拟圆柱的运动边界,对均匀来流中的横向振荡圆柱绕流场进行数值模拟,计算了振荡圆柱升力系数、阻力系数随时间的变化曲线,以及不同相位时的流线矢量图和涡量等值线分布图。为验证模型的可靠性,对静水中的振荡圆柱流场进行模拟,与实验及数值计算结果吻合较好。
文摘The wave force exerted on vertical piles of offshore structures is the main criterion in designing them.In structures with more than one large pile,the influence of piles on each other is one of the most important issues being concerned in past researches.An efficient method for determining the interaction of piles is introduced in present research.First the wave force is calculated by the exact method using the diffraction theory,then in the finite difference numerical method the force is calculated by adding the velocity potentials of each pile and integration of pressure on their surface.The results showed that the ratio of the wave force on each of the double piles to a single pile has a damped oscillation around unity in which the amplitude of oscillation decreases with the increase in the spacing parameter.Also different wave incident directions and diffraction parameters were used and the results showed that the numerical solution has acceptable accuracy when the diffraction parameter is larger than unity.
基金supported by the National Natural Science Foundation of China (Grant No. 10832001)the Innovation Foundation of BUAA for PhD Graduates
文摘Particle Imaging Velocimetry （PIV） is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity along the wake central-line and the mean vertical velocity around the trailing edge of the flexible tail can be greatly increased with the tail length. Meanwhile, the longer the flexible tail is, the larger its deformation is. In order to study the influence of flexible tail length on the wake pattern of the experimental model, the relationships between the swirling strength Aci of vortex structure near the tail end and the velocity of tail trailing edge have been revealed. Moreover, the convection tracks and the Aci of vortex cores for different flexible tails are discussed.
