Study On Computation Factors Of One Dimensional Water Surface

In the channel regulating work, regulating structures such as groyne, longitudinal dam are used to change water depth, water velocity and water surface slope of the channel. These structures will also change the distribution of velocity and result in variation of the kinetic energy correction factor. This paper studies on the law of the kinetic energy correction factor near a groyne by a flume experiment basing on one dimensional energy equation of steady flow.The relationships between the kinetic energy correction factor near a groyne and the discharge, the groyne length, the groyne angle, the longitudinal distance from the groyne are studied by a flume experiment. The analysis on the experiment result displays that the kinetic energy correction factor is mainly affected by the groyne length, angle, and the longitudinal distance, but not influenced by the discharge if water depth is less than the groyne height. If the measured water surfaces at two or more discharges are known, we can compute the roughness at another discharge by three roughness interpolation methods. With analysis on the error of these three methods, a more exact interpolation method will be attained. With the mathematical model of one dimensional water surface founded before, the hydraulic factors of four design schemes under four discharges in Panjiatai shoal are computed. The four design schemes are compared and a better design scheme is recommended. Comparing the computation results of these four design schemes we get variation of the kinetic energy correction factor near groynes in Panjiatai shoal when water depth is less than the groyne height. The variation characteristics of the kinetic energy correction factor in Panjiatai shoal is different from the experiment results because the effect of groynes in the Panjiatai shoal is simulated by three parameters together.The research result of this paper offers more theory reference when evaluating the computation factors of one dimensional water surface in the channel regulating work, it also makes a good foundation for further research on hydraulic factors near a regulating structure in the future.