90°弯道T型丁坝水力特性和数值模拟研究

Numerical simulation on the hydraulic characteristics of T-shaped spur dike in a 90° bend

利用雷诺平均Navier-Stokes(RANS)方程和k-ω涡粘紊流模型,研究在无丁坝、直线型丁坝、T型丁坝三种工况下90°弯道水流中的水力特性.研究结果表明:与直线型丁坝相比,T型丁坝下游形成的回流区长度约缩短15%,宽度约缩窄25%;对水面壅高、横纵比降的影响程度较小,且将横向环流移向河道中心,更加合理的减轻环流对岸边的水毁破坏;河床切应力突增率低于直线型丁坝,强度顺河道向下游衰退更快.综合比较,T型丁坝是一种优于直线型丁坝的坝型.

This paper analyze flow hydraulic characteristics in the 90°bend with three conditions about no spur dike,straight rectangle spur dike and T-shaped spur dike by using Reynolds Average Navier -Stokes equation and k-ω eddy viscosity turbulence model.Comparison with the straight rectangle spur dike,the length of backflow at downstream of T-shaped spur dike is shorten about 15 percent and the width shrunk about 25 percent.The effect on freeboard and transverse and longitudinal slope is slightly.Also the lateral circulation is transferred to the center of river and relieve the erosion damage to bank.The rate of change in bed-shear stress is lower than the straight rectangle spur dike and its intensity decays towards downstream.As a result T-shaped spur dike is more effective than the straight rectangle spur dike in bend.