带有复杂齿条结构的弦杆是自升式平台桁架式桩腿的核心结构，也是保证整座平台结构安全稳定的关键结构。弦杆环境载荷的计算通常采用半理论半经验的方法，鲜有针对此类钝体的流场机理进行研究。基于N-S控制方程，选取适合具有较大压力梯度的RNG k-ε模型研究弦杆绕流流场，对不同雷诺数、不同流向下的二维弦杆绕流流场进行数值模拟，研究带复杂齿条结构的弦杆绕流流场特性，包括尾流流场形式、升阻力系数，以及漩涡脱落频率随Re的变化规律。研究结果表明：带复杂齿条弦杆的绕流流场与圆柱形结构的绕流流场有较大的区别，且弦杆齿条与来流方向的夹角不同时，其尾流流场差异较大；在较高Re下，当流向角为90°时，弦杆的尾流负压区和尾涡区域均变大，水动力系数也增加。对弦杆绕流流场的研究分析，为弦杆环境载荷的计算、保证自升式平台的安全性提供了理论支撑。
The chord with complex rack structure is the core structure of the truss leg of the jack up, and it is also the key structure to ensure the safety and stability of the whole platform. The environmental load of chord usually adopts the semi theoretical and semi empirical method, and few studies are carried out on the flow field mechanism of this kind of bluff body. Based on the N-S governing equations, RNG K-ε model with large pressure gradient is used to study the flow field around the chord. The two-dimensional flow field around the chord is simulated under different Res and different flow directions. The characteristics of the flow field around the chord with complex rack structure are studied, including the wake flow field form, lift and drag coefficient, and the variation of vortex shedding frequency. The results show that the flow field around the chord with complex rack is more complex compared with the cylindrical structure, and the wake flow field is different when the angle between the rack and the incoming direction is different. The wake negative pressure area and the wake vortex area of the chord become larger at higher Re when the angle between the rack and the incoming direction is 90°, and the hydrodynamic coefficient also increases. The research and analysis of the flow field around the chord provide theoretical support for the environmental load of the chord and the guarantee of the safety of the jack up.
2021,43(6): 100-105 收稿日期：2021-01-06
DOI：10.3404/j.issn.1672-7649.2021.06.019
分类号：U674.38;P751
基金项目：国家自然科学基金青年项目(51909148)；山东交通学院博士科研启动基金资助(BS2018001，BS201901016)；山东交通学院攀登计划(SDJTUC1802)
作者简介：林海花(1979-)，女，博士，高工/副教授，主要研究方向为船舶与海洋工程设计与评估
参考文献：
[1] 朱亚洲, 孙承猛, 林海花, 等. 自升式平台桁架式桩腿结构选型方法[J]. 哈尔滨工业大学学报, 2016, 48(10): 155–161
[2] CAO Y, NIE W, HU X, et al. Parameter sensitivity study of dynamic response for jack-ups by FEM analysis[J]. Ocean Engineering, 2016, 124(15): 125–134
[3] ALAM, M. M., MEYER, J. P. Global aerodynamic instability of twin cylinders in cross flow[J]. Journal of Fluids Structure,, 2013, 41: 135–145
[4] LIN Y F, BAI H L, ALAM M M, et al. Effects of large spanwise wavelength on the wake of a sinusoidal wavy cylinder. J. Fluids. Struct., 2016, 61: 392–409.
[5] GUSTAVO R. S. ASSI, PETER W. BEARMAN. Vortex-induced vibration of a wavy elliptic cylinder[J]. Journal of Fluids Structure, 2018, 80: 1–21.
[6] 谷家扬, 蒋汝斌, 渠基顺. 不同流向下低质量比方形四立柱涡激运动特性研究[J]. 船舶工程, 2015, 37(1): 40–44
[7] 端木玉, 万德成. 不同长细比圆柱绕流的大涡模拟[J]. 水动力学研究与进展(A辑), 2016, 31(1): 295–302
[8] 林凌霄, 陈威, 林永水. 单双圆柱涡激振动数值模拟研究[J]. 舰船科学技术, 2020, 42(7): 49–53
LIN Ling-xiao, CHEN Wei, LIN Yong-shui. Numerical simulation of vortex-induced vibration of single or double circular cylinders[J]. Ship Science and Technology, 2020, 42(7): 49–53
[9] 孙洪源, 黄维平, 李磊, 等. 低长径比浮式圆柱涡激运动实验研究[J]. 船舶力学, 2019, 23(4): 405-411.
SUN Hong-yuan, HUANG Wei-ping, LI Lei,et al. Experimental study on vortex induced motions of a floating cylinder with low aspect ratio[J]. Journal of Ship Mechanics, 2019, 23(4): 405-411.
[10] 高云, 张壮壮, 杨斌等. 圆柱体横流与顺流方向涡激振动耦合模型研究[J]. 振动与冲击, 2020, 39(11): 22-30.
[11] 武磊, 赵伟文, 万德成. 不同浸没长度下串列双立管涡激振动数值模拟[J]. 海洋工程, 2020, 38(3): 52–61
WU Lei, ZHAO Wei-wen, WAN De-cheng. Numerical simulations on vortex-induced vibrations(VIV) of two tandem risers with different submerged lengths[J]. The Ocean Engineering, 2020, 38(3): 52–61
[12] 王福军. 计算流体动力学分析—CFD软件原理与应用. 北京: 清华大学出版社, 2004.
[13] 杨春蕾, 朱仁传, 缪国平, 等. 基于RANS和DES法船体绕流模拟及不确定度分析[J]. 上海交通大学学报(自然版), 2012, 46(3): 430–435
[14] 赵伟文, 万德成. 用SST-DES和SST-URANS方法数值模拟亚临界雷诺数下三维圆柱绕流问题[J]. 水动力学研究与进展(A辑), 2016, 31(1): 1–8
ZHAO Wei-wen, WAN De-cheng. Numerical study of 3D flow past a circular cylinder at subcritical Reynolds number using SST-DES and SST-URANS[J]. J. Chinese Journal of Hydrodynamics(A), 2016, 31(1): 1–8
