格栅对海底阀箱剪切层处水动力特性的影响分析

Effect of grids on hydrodynamic characteristics of a suction box at shear layer

对比船舶海底阀箱剪切层处有无格栅情况时剪切层处的水动力特性,以不可压缩Navier-Stokes方程为控制方程,利用计算流体力学软件CFX中的LES(Larger eddy simulation)湍流模型,采用Simple算法进行不同箱型结构流激振荡问题的数值计算与分析。数值计算结果表明:阀箱口格栅的存在使得剪切层处流体的流态更加复杂,且具有大量的小涡从箱口导边脱出,在向随边运动中破碎;格栅的存在使得剪切层处稳态压力系数增大,脉动压力系数减小,使剪切层的振荡频率呈现单峰现象,且振频值增大。

A contrast method was applied to study the hydrodynamic character of a marine suction box at shear layer between grids and no grids.The incompressible Navier-Stokes equations were taken as the control equations while the advanced turbulent model LES in CFX softwave and the simple algorithm were used to carry out the numerical computation of problems of flow induced oscillation.The numerical results showed that the pattern of fluid at shear layers is more complex when the grids exist at the box mouth;additionally,a lot of small eddies shed continuously from the leading-edge of the box mouth,and move continuously to trailing-edge;moreover,the value of the static pressure coefficient increases due to the grids existing,while the fluctuating pressure coefficient reduces;at the same time,the oscillating frequency of the shear layer presents the single-peaked value which is larger than that without grids.