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在圆形断面渠槽中,为调控流量,常常设置外部轮廓按圆半径成形的平面闸门,并且,闸门的直径D_2大于圆形渠槽的直径D_1,即D_2>D_1。在闸门开启的情况下,两个圆周线之间形成的闸孔,具有弯月形(图1a)。水流经过这样的闸孔,因形成横向波,将是很复杂的,而水面形状简直不可预测。确定闸孔水流的垂向收缩系数ε,象在矩形情况下来做,是不可能。闸孔出流有明显的三维特征。在设计实践中引用的一些公式,只适用于二维情况。利用这
In the circular cross-section of the channel, in order to regulate the flow, often set the outer contour of the plane formed by the radius of the round gate, and the gate diameter D_2 greater than the circular channel diameter D_1, that D_2> D_1. With the gate open, the gate hole formed between the two circumferential lines has a meniscus (Figure 1a). Flow through such gates, due to the formation of transverse waves, will be very complicated, and the shape of the water is simply unpredictable. It is not possible to determine the vertical shrinkage factor ε of the gate flow, as in the case of a rectangle. Gate flow out of the obvious three-dimensional characteristics. Some formulas quoted in design practice apply only to two-dimensional situations. Use this