摘要
水下大直径淹没圆柱在波流共同作用下的冲刷特性与非淹没情况有较大差别。在波流水槽中开展局部冲刷试验,将大直径淹没圆柱模型安装在中值粒径0.22 mm的平底沙床内,改变波浪波高和周期、水流流速和方向、圆柱淹没率,测量圆柱周围流速变化,记录柱周冲深发展历时,运用激光地形仪测量冲刷坑的地形形态,分析了淹没率S r和相对高度h c/D对准平衡冲深的影响。结果表明,相同入射波流条件下,随相对柱高h c/D降低,冲刷发展速率、冲坑半径和深度都随之减小。当相对柱高h c/D>1时,冲深随柱高增长速率较快直至达到临界值。准平衡冲刷坑呈“倒勺状”,沿圆柱左右两边呈对称分布,柱前呈半环状;圆柱正后方淤积成“马鞍状”沙丘。
The characteristics of local scour around large-diameter submerged cylinders are quite different from the non-submerged ones under combined wave and current conditions.Local scour model tests are carried out in a wave-current flume.A submerged cylinder model was installed in a flat sand bed.The flow velocity around the model was measured,and the development of the scour depth was recorded under various waves,current velocities,current directions and submergence rates.A laser scanner was used to generate the geometry of the equilibrium scour hole.The influence of the submergence rate S r and the relative cylindrical height h c/D on the equilibrium scour depth is analyzed.The results show that under the same incident wave current conditions,as the relative cylindrical height h c/D decreases,the scour development rate,the scour hole radius and the scour hole depth decrease.When the relative cylindrical height h c/D is larger than 1,the scour depth increases rapidly as the cylinder height increases until a critical value of h c/D is reached.The quasi-equilibrium scour hole is in the shape of a“flipped spoon”.The scour hole is symmetrically distributed along the left and right sides of the cylinder.The front of the cylinder is a semi-annular scour hole.A“saddle-shaped”dune is formed due to accumulation of sand scoured away from the cylinder.
作者
程永舟
吕行
王文森
黄筱云
夏波
CHENG Yongzhou;LYU Xing;WANG Wensen;HUANG Xiaoyun;XIA Bo(School of Hydraulic Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China)
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2019年第6期872-881,共10页
Advances in Water Science
基金
国家自然科学基金资助项目(51679015)~~
关键词
波流作用
淹没圆柱
局部冲刷
冲刷形态
准平衡冲刷深度
combined waves and current action
submerged cylinder
local scour
scour topography
quasi-equilibrium scour depth
