T型丁坝坝翼与坝身夹角及坝轴线中心角对90°弯道水流的影响  

Influence of the angle of spur dike wing and spur dike and the central angle of spur dike axis of T- shaped spur dike in a 90° bend

作　　者：张挺[1] 巨淑君 陈虹[1] 

机构地区：[1]福州大学土木工程学院,福建福州350116

出　　处：《福州大学学报（自然科学版）》2015年第1期106-110,134,共6页Journal of Fuzhou University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51109149);福建省自然科学基金资助项目(2011J01307)

摘　　要：结合下挑丁坝和弯道边界条件的特点,利用三维数值模型研究90°弯道中设置T型丁坝后,丁坝坝翼与坝身的夹角θ以及坝轴线中心角α对回流区大小、丁坝附近横截面主流区流速、横向环流以及最大河床切应力的影响.研究结果表明,回流宽度随θ的减小而逐渐递增,回流长度在θ=75°时,相对最短,并且回流长度随α的减小而减小.丁坝附近横截面主流区流速随着θ的减小而减小、当θ减小到45°时会增大,丁坝上下游各截面的流速随α减小略微减小.河床切应力最大值与平均切应力之比τmax/τ0随Fr的增大呈递减趋势,随θ的减小呈现先递减再反向增加的趋势,当θ=75°时,τmax/τ0的相对值最小;α越小,τmax/τ0越小.综合研究表明,T型丁坝坝翼与坝身夹角θ为75°且坝轴线中心角α为30°时,可以更好地发挥T型丁坝的体型优势.This paper researches on the effects of hydraulic characteristics caused by the parameters θand α meant respectively the angle between spur dike wing and spur dike and central angle of spur dike axis in the 90° bend by using 3D numerical simulation. The results indicate that the width of backflow increases with the decrease in θ and the width of backflow is relatively shortest at θ = 75°,while the main- flow velocity decreases with the decrease in θ and it will raise when θ dropped to 45°along with it will decline slightly around spur dike. Besides the length of backflow decreases with the decrease in α. The ratio of the maximum and the average bed- shear stress increases with the increase in Froude number and decreases with the decrease in α,also it provides a trend that the shear stress will decline firstly and then increase with the decrease in θ as well as the ratio is relatively minimum atθ = 75°. It is evident that the T- shaped spur dike will be applied in its type advantage at θ = 75°andα = 30°.

关 键 词：T型丁坝 坝翼 坝身 夹角 中心角 水力特性 弯道 

分 类 号：TV653[水利工程—水利水电工程]