Research on hydrodynamic characteristics of cylinder planing

回转体滑水航行流体动力特性研究

¹ School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
² Xi'an Qing'an Electric Control Co., LTD, Xi'an 710077, China
³ The 705 Research Institute, China State Shipbuilding Corporation Limited, Xi'an 710077, China

Received: 30 March 2020

Abstract

This paper selects SST k-w turbulence model and VOF wave to construct a numerical calculation model of moving body planning on a flat free surface based on STAR-CCM+ numerical simulation software. The construction model is checked through foreign classic literature, and the numerical simulation results are in good agreement with the experimental results. The hydrodynamic numerical errors are less than 5%, which is within the engineering error range. The model can be used for the numerical simulation of the planning cylinder. In this paper, it is used to simulate the planing process of cylinder with different speeds and different submerged depths, and the flow field characteristics and hydrodynamic characteristics in the planing process are obtained. The results show that waves appear at the tail and the tail liquid splashes to form a water splash during the planing process of the cylinder on a flat surface. The higher the speed of the planning cylinder is, and the deeper the submersion depth, the more pronounced waves at the tail. When the cylinder has a Fr number C_v≥8, the hydrodynamic force of the cylinder is almost unchanged, and it is not affected by the speed. But when C_v=3, the hydrodynamic characteristic coefficient is higher. The drag coefficient is 20% higher than that in the high-speed (C_v≥8) planing process. The lift coefficient is 3 times of high-speed planing lift coefficient. It is related to the surface pressure and frictional force distribution of cylinder during the low-speed planing. There is a linear relationship between the drag coefficient and the submerged depth during the cylinder planing at different submerged depths.

摘要

基于STAR-CCM+数值仿真软件，选用SST k-w湍流模型，采用VOF波构建运动体在静水面滑水数值计算模型。通过国外经典文献对构建模型进行校核，数值模拟结果与实验结果吻合性较好，流体动力数值误差均小于5%，在工程误差范围内，模型可用于回转体滑水航行工况的数值模拟计算。对回转体在不同速度、不同淹没深度滑水工况进行数值模拟，研究其流场特性和流体动力特性。结果表明，回转体在静水面滑水过程中，尾部波浪兴起，液体飞溅形成水花，滑水速度越高、淹没深度越深，尾部兴波越明显；回转体在C_v≥8时，流体动力系数几乎不变，其不受速度大小的影响，而在C_v=3时，流体动力系数较高，阻力系数高于高速(C_v≥8)滑水阻力系数20%，升力系数是高速滑水升力系数的3倍，其与回转体在低速滑水过程中表面压力和摩擦力作用分布有关；回转体在不同淹没深度滑水过程中，阻力系数与淹没深度呈线性关系。