摘要
根据势流理论给出任意运动的2个水下无升力物体间流体动力干扰的二维和三维计算模型.从壁面附近圆柱干扰力计算结果出发,指出水下物体相互接近过程中,理论上存在某种干扰最小的路径.采用3种不同的网格划分比例计算回转椭球体附加质量,单元数确定时,加密纵向网格则与纵向运动有关的计算精度提高,横向的精度降低,因此网格划分应合理分配纵横比例.对三维Rankine体进行了壁面干扰规律的模型试验和计算研究,间距较大时物体受到壁面的吸力,随间距的减小,该吸力先逐渐增加后减小,最后变为排斥力,分布源计算值与试验值的比较表明:分布源法可有效预测壁面间距较大情况下的流动干扰力,随着Reynolds数的增加,分布源法有效性的壁面间距下限增大.论文中的数值模型也适用于多个无升力物体作6自由度运动的情况.
According to potential flow theory, 2D and 3D mathematical models were presented for the interaction forces between two non-lifting bodies moving near to each other. From the computation results of a circular cylinder near a plane wall, the phenomenon was observed that the minimal interaction path exists for underwater bodies in approaching process in theory. The added masses of spheroid were calculated using three different longitudinal-to-transverse grid-dividing ratios. A comparison of analytical values shows that if the panel number is fixed, giving grid refinement in longitudinal direction, the precision of added masses relating to longitudinal movement increases, while the results' precision relating to transverse decreases. Thus, the longitudinal-to-transverse ratio needs to be chosen properly in grid dividing. Experiments and calculations were carried out for a 3D Rankine ovoid moving parallel to a wall. There exists suction force exerting on the ovoid when the wall clearance is large. With the decreasing of wall clearance, the suction force increases and then decreases, and finally changes into repulsion force. Calculation results and test data show that the source-distribution method can give good prediction of hydrodynamic interaction forces in a large wall clearance. The minimum clearance that this computing method is applicable increases with the increase of Reynolds number. The models here are also applicable to several non-lifting bodies in arbitrary motion in an unbounded fluid domain.
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2005年第1期1-6,共6页
Journal of Harbin Engineering University
基金
国防科学技术工业委员会基础研究基金资助项目(513060102)
哈尔滨工程大学基础研究基金资助项目(HEUF04001).
关键词
水动力干扰
壁面效应
面元法
Mathematical models
Potential flow
Reynolds number
Three dimensional
Two dimensional
Underwater structures
