
科学技术与工程

中国技术经济学会
波流共同作用下跨海大桥倾斜桥墩水动力特性
Hydrodynamic Characteristics around Inclined Piers of Sea-crossing Bridges under Waves and Current
跨海大桥桥墩时刻受到水流和波浪的冲刷作用,桥墩周围水流环境复杂,基础易出现局部冲刷,可能危及桥梁安全。基于计算流体力学(computational fluid dynamics, CFD)和开源软件OpenFOAM开展圆端形桥墩绕流流场的三维数值模拟,研究不同倾斜角度和长宽比(L/D)条件下的桥墩周围流场发展过程,涡流发展情况以及荷载变化规律。结果表明:波流作用下,桥墩后方形成对称分布的涡旋并呈周期性变化。一个周期内,当波谷传递到桥墩时,后方尾涡区范围增大,涡旋不断变大并向后移动,在波峰到达桥墩前达到最大,后逐渐减小消散;随着向下游倾斜的角度增大,斜墩趋向于流线形,尾涡减小,桥墩所受水平荷载减小;随着长宽比增大,桥墩后方的尾涡区范围减小,水平荷载增大。在长宽比为1 ~ 3,倾斜角度为-30° ~ 30°范围内,当长宽比为1,倾斜角度为10°时桥墩所受荷载最小,该结果可为跨海大桥桥墩冲刷设计提供参考。
The piers of sea-crossing bridge are always subject to the scouring effect of flow and waves. The flow environment around the piers is complex. There is a risk of foundation erosion, endangering the safety of the bridge. Based on computational fluid dynamics(CFD) and the open-source software OpenFOAM, three-dimensional numerical simulations of the flow field around the inclined oblong pier were conducted with different inclination angles and length-to-width ratios(L/D). The results demonstrate that under the influence of wave and current, a symmetrically distributed vortex is formed behind the pier and undergoes periodic changes. The wake vortex constantly strengthens and moves backward as the trough approaches the pier. It reaches the maximum than gradually reduces and dissipates before the crest reaches the pier. With an increased downstream inclination angle, the pier tends to be streamlined, resulting the decreasing of wake vortex intensity and the horizontal load of pier. As the length-to-width ratio(L/D) increases, the tail vortex area behind the bridge pier decreases and the horizontal load increases. Within the range of L/D = 1 to 3 and a range of -30° to 30°, the minimal load on the pier is achieved when L/D is 1 and inclination angle is 10°.
波流耦合作用 / 倾斜桥墩 / 局部冲刷 / OpenFOAM
combined waves and current / inclined pier / local scour / OpenFOAM
/
| 〈 |
|
〉 |