插有缓变曲线弯道水流运动的三维数值模拟

Three-dimensional Numerical Simulation of the Flow Movement in Bend Inserted the Transition Curve

若能够有效地利用数值模拟来揭示弯道水流运动和床面冲淤流变规律,将可以节省大量的人力、财力和时间。为此,通过引入可以舒缓水流冲击力和离心力作用的缓圆缓和对称凸型这2种新的弯道型式,减轻水流对河床及堤身、堤脚的冲蚀破坏。数值模拟结果表明:缓圆缓弯道和对称凸型弯道的水面超高及横比降较圆弯道大幅减少;除弯道进口外,插有缓变曲线的2种弯道的凹岸近底流速均小于圆弯道,凸岸的弯道进口附近及过弯顶断面后,这2种弯道的近底流速较圆弯道明显减小;插有缓变曲线的2种弯道的深槽明显比圆弯道的要浅。

The study on bend flow is important for the development of rivers,sediment protection and river evolution. If the numerical simulation can be effectively used to reveal the law of flow and scouring and silting on bed surface,it will save a lot of manpower,money and time. In this study,two kinds of curves： slow-round-slow bend and symmetric convex curves,which can be introduced to decrease the impact force of the current and to prevent scouring along the river bed,dike and feet of the dike. Through the numerical analysis,some results can be concluded： the ultra-high and horizontal surface slope of the slow-round-slow bend and symmetric convex curves are significantly reduced compared with the round bend; In addition to the corner imports,on cave bank,the bottom velocity of slow-round-slow bend and symmetric convex curves is less than that of the round bend,convex bank of imports and cornering near top cross-section,the flow velocity near bottom of these two bends is significantly smaller than that of the round one; The deep groove of these two inserted with graded curves is obviously shallower than that of the round bend from the figure of vertical and horizontal erosion and deposition on the bed surface.