丁坝挑角及长度对回流区流动特性影响的数值模拟

Numerical simulation of the influence of spur dike angle and length on flow characteristics in recirculation zone

为探究丁坝挑角及长度对坝后回流区流动特性的影响,利用计算流体力学(CFD)方法,模拟宽浅河道中丁坝挑角上挑60°、正挑、下挑120°,及丁坝投影长度为0.12,0.2,0.3 m条件下回流区流场和湍动能及湍流黏度的分布。结果表明:丁坝回流区最大相对长度L/B及最大相对宽度W/B与丁坝相对投影长度b1/B成正相关;湍动能沿着流动分离区域向两侧及下游扩散衰减,其最大值出现在坝后流动分离处;丁坝的投影长度和挑角直接影响湍动能和湍流黏度的大小和分布;随着水深增加,湍动能和湍流黏度分布规律不变,其值随着水深的增加而小幅减小。

To study the influence of the pick angle and length of spur dike on the flow characteristics of recirculation zone behind the spur dike, the computational fluid dynamics(CFD) method was applied to simulate the flow fields and the distributions of turbulent kinetic energy and turbulent viscosity under three pick angles(60°, 90° and 120°) and three projection lengths(0.12 m, 0.2 m and 0.3 m) of spur dike. The results show that the maximum relative length L/B and width W/B of recirculation region are positively correlated with the relative projection length of spur dike b1/B. The turbulent kinetic energy diffuses and attenuates along the flow separation zone to both sides and downstream, and the maximum value is located at the flow separation zone behind the spur dike. The projective length and angle directly affect the size and distribution range of turbulent kinetic energy and turbulence viscosity. With the increase of water depth, the distribution patterns of turbulent kinetic energy and turbulent viscosity remain the same, and the values decrease slightly with the increase of water depth.