定常流中不同淹没深度下水平圆柱载荷分析

Analysis of horizontal cylindrical loads under differentsubmerged depths in a steady flow

基于CFD方法的数值模拟对水平圆柱与定常流相互作用的问题进行研究,首先建立含有自由液面的定常流条件下固定与刚体运动圆柱体的二维数值计算模型,在建立的模型中分别对不同淹没深度、不同流速、不同圆柱尺寸、不同雷诺数下水平圆柱的载荷进行分析计算.结果表明:随着圆柱淹没深度的增加,圆柱受力先增加后减小;靠近自由液面时,淹没深度是影响受力的重要原因,其中水平系数对淹没深度的敏感程度比垂向系数小,主要是由自由液面波动引起的反射和阻塞所导致;S/D<-2.5(S为圆心到水平面的距离,D为圆柱直径)时可以忽略自由液面的影响,固定与刚体运动圆柱体均在S/D=-1时水平系数达到最大,S/D=-0.5时,垂向系数达到最大;随着雷诺数的增加,运动圆柱水平系数平均值先增再减,垂向系数平均值不断减小.

Numerical simulation based on CFD method is used to study the interaction between a horizontal cylinder and a steady flow.Firstly,a two-dimensional numerical calculation model of fixed and rigid moving cylinders is established under the condition of steady flow with free liquid surface.Analysis and calculation are carried out for loads of horizontal cylinders under different submerged depths,different flow rates,different cylinder sizes,and different Reynolds numbers.The results show that with the increase of the submerged depth of the cylinder,the force on the column increases first and then decreases.When it is close to the free liquid surface,the submerged depth is an important factor affecting the force,and the horizontal force is less sensitive to the submerged depth than the vertical force.It is mainly caused by reflections and blockages due to free surface fluctuations.The influence of free liquid surface can be ignored when S/D<-2.5(S is the distance from the center of the circle to the horizontal plane),and the horizontal force of both fixed and elastic cylinders reaches its maximum when S/D=-1,and the vertical force reaches the maximum when S/D=-0.5.With the increase of Reynolds number,the average value of the horizontal coefficient increases continuously,and the amplitude of the vertical coefficient first increases and then decreases.