Although submerged vertical circular cylinders have been widely applied in engineering fields, there are no systematic study on the flow pattern and turbulence characteristics in the flow field around the submerged vertical circular cylinders.In view of this,we carried out indoor flume experiment with different slopes and accurately measured the instantaneous velocity field around the submerged vertical circular cylinders. According to the test result, we analyzed the impact of the submergence ratio on the vertical distribution of three-dimensional flow velocity and turbulence intensity along upstream and downstream vertical symmetry plane of the submerged vertical circular cylinders.On this basis, we researched the variations of scour strength of downstream flow, horseshoe vortex and tail flow vortex with submergence ratio, and revealed the mechanism of submergence ratio affecting local scour by clear water around the submerged vertical circular cylinders. Research results show that 1) increasing submergence ratio could reduce the effective length of vertical circular cylinder above water surface and weaken the resistant flow and disturbance of the cylinder on water; 2) the scour capacity of downward flow in the upstream of cylinder, horseshoe vortex around the cylinder, and tail flow vortex obviously decreases, which reduces the probability of sediment around vertical circular cylinder being eroded by vortex.
Key words
submerged vertical circular cylinder /
flow pattern /
turbulence characteristics /
scour mechanism /
submergence ratio
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] 房世龙,钱俊峰,施小飞.圆柱桥墩清水局部冲刷透水三杆架体防护特性试验研究[J]. 水电能源科学,2015, 33 (8):98-102.
[2] SHAMLOO H, RAJARATNAM N, KATOPODIS C. Hydraulics of Simple Habitat Structures[J]. Journal of Hydraulic Research, 2001, 39(4):351-366.
[3] SALAHELDIN T M,IMRAN J,CHAUDHRY M H.Numerical Modeling of Three-Dimensional Flow Field Around Circular Piers[J].Journal of Hydraulic Engineering, 2004,130(2):91-344.
[4] 尹德操,尤云祥,魏 岗.均匀流中直立圆柱体绕流三维数值模拟[J].海洋工程,2007,25(4):77-83.
[5] 刘 松,符 松.串列双圆柱绕流问题的数值模拟[J].计算力学学报,2000,17(3):260-266.
[6] AKIB S, JAHANGIRZADEH A, BASSER H. Local Scour Around Complex Pier Groups and Combined Piles at Semi-integral Bridge[J]. Journal of Hydrology & Hydromechanics, 2014, 62(2):108-116.
[7] 房世龙,陈 红,施小飞.三杆六脚体对桥墩周围流场影响的试验研究[J].人民长江,2015,46(10):61-66.
[8]DEY S, RAIKAR R V, ROY A, et al. Scour at Submerged Cylindrical Obstacles under Steady Flow[J]. Journal of Hydraulic Engineering, 2008,134(1):105-109.
[9]ZHAO Ming, CHENG Liang, ZANG Zhi-peng. Experimental and Numerical Investigation of Local Scour Around a Submerged Vertical Circular Cylinder in Steady Currents[J]. Coastal Engineering,2010,57(8):709-721.
[10]SARKAR A, RATHA D. Flow Around Submerged Structures Subjected to Shallow Submergence over Plane Bed[J]. Journal of Fluids and Structures, 2014, 44 (2):166-181.
[11]SADEQUE M A, RAJARATNAM N , LOEWEN M R. Flow around Cylinders in Open Channels[J]. Journal of Engineering Mechanics, 2008, 134(1):60-71.
[12]房世龙.局部冲刷坑形成影响桥墩附近流场特性的试验研究[J].水运工程,2009,(11):143-152.
[13]张 磊,佘小建.环行桩群加承台基础结构局部冲刷试验研究[J].长江科学院院报,2011,28(11):10-18.
[14]张琪琦,孙西欢,李永业.圆柱体绕流环隙流场轴向流速及水力损失试验研究[J].长江科学院院报,2015,32(4):51-58.
[15]房世龙,陈 红,施小飞.桥墩清水局部冲刷减速不冲防护技术试验研究[J].重庆交通大学学报(自然科学版) ,2016,35(3):71-77.
[16]吴新生,韩向东,黄卫东,等.新型ADV流速仪在桥墩模型试验中的应用[J].长江科学院院报,2011,28(11):104-109.
PDF(1810 KB)
