基于出射流速的反弧鼻坎挑距计算

为了提高挑距计算精度及进一步补充和完善挑距理论计算方法,从出射流速的角度提出水舌上、下缘挑距的计算方法。该方法基于反弧鼻坎上流线同心圆假设,同时考虑反弧段离心力压强和静水压强,推导了鼻坎反弧段势流流速分布函数,利用出坎断面流速分布函数,得到水舌上、下缘出射流速的理论计算式,从而实现水舌上、下缘挑距的计算。采用模型试验和原型观测资料对计算方法进行了验证,结果表明,在相对出坎水深为0.15～0.25范围内,该方法对水舌上、下缘挑距均有较好的计算精度。

Calculation of jet trajectory distance of flip bucket based on takeoff velocity

To improve the precision and to further complement and perfect the calculation theories for jet trajectory distance, a calculation method for the upper and lower jet trajectory distances in the perspective of the takeoff velocity was proposed. Based on the concentric circle assumption of the streamline on the flip bucket with the consideration of the centrifugal force and the hydrostatic pressure, the potential flow velocity distribution function was derived. Theoretical calculation formulas for the velocity of the upper and lower trajectory were obtained from the takeoff velocity distribution and then the jet trajectory distance calculation was realized. The calculation method was verified by both model tests and prototype observation datum, showing a reasonable accuracy for the upper and lower trajectory distance when the relative takeoff water depth is between 0. 15 and 0. 25.