In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asym...In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asymmetric trapezoidal flume with a length of 7 m and a width of 0.304 m is considered,with the bottom of the flume transversely inclined at an angle of m=0.296 and vertical lateral sides.The corresponding inflow Froude number is allowed to range in the interval(1.40<F1<6.11).The properties of this jump are compared to those of hydraulic jumps in channels with other types of cross-sections.A relationship for calculating hydraulic jump efficiency is proposed for the considered flume.For F1>5,the hydraulic jump is found to be more effective than that occurring in triangular and symmetric trapezoidal channels.Also,when■mes>8 and■>5,the hydraulic jump in the asymmetrical trapezoidal channel downstream of a parallelogram sluice gate is completely formed as opposed to the situation where a triangular sluice is considered.展开更多
The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, Chi...The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.展开更多
Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater ret...Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed. Different problems of silting near tidal sluices for different types of estuaries are summed up, at the same time, corresponding methods are given to solve these problems, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.展开更多
This paper present the effect of the lower gate lip on the coefficient of contraction, velocity and discharge which have been made in a rectangular flume with four gates opening from (2 to 4.5) cm, five different disc...This paper present the effect of the lower gate lip on the coefficient of contraction, velocity and discharge which have been made in a rectangular flume with four gates opening from (2 to 4.5) cm, five different discharges from (6.2 to 18.15) l/s and five different gate cases (vertical and inclined vertically) by angle (45)° with and opposite flow direction with horizontal and sharp lower lip. The values of coefficients of contraction (Cc) and discharge (Cd) increases when gate slope increases with flow direction and the lower lip is horizontal, these increases are (16)% and (18)% respecttively, while these values decreases when gate slope increases opposite flow direction and the lower lip is horizontal these decreases are (13)% and (11)% respectively. The values of coefficient of velocity (Cv) remain constant and don’t effect with changes of gate slope or gate lip.展开更多
文摘In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asymmetric trapezoidal flume with a length of 7 m and a width of 0.304 m is considered,with the bottom of the flume transversely inclined at an angle of m=0.296 and vertical lateral sides.The corresponding inflow Froude number is allowed to range in the interval(1.40<F1<6.11).The properties of this jump are compared to those of hydraulic jumps in channels with other types of cross-sections.A relationship for calculating hydraulic jump efficiency is proposed for the considered flume.For F1>5,the hydraulic jump is found to be more effective than that occurring in triangular and symmetric trapezoidal channels.Also,when■mes>8 and■>5,the hydraulic jump in the asymmetrical trapezoidal channel downstream of a parallelogram sluice gate is completely formed as opposed to the situation where a triangular sluice is considered.
文摘The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.
文摘Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed. Different problems of silting near tidal sluices for different types of estuaries are summed up, at the same time, corresponding methods are given to solve these problems, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.
文摘This paper present the effect of the lower gate lip on the coefficient of contraction, velocity and discharge which have been made in a rectangular flume with four gates opening from (2 to 4.5) cm, five different discharges from (6.2 to 18.15) l/s and five different gate cases (vertical and inclined vertically) by angle (45)° with and opposite flow direction with horizontal and sharp lower lip. The values of coefficients of contraction (Cc) and discharge (Cd) increases when gate slope increases with flow direction and the lower lip is horizontal, these increases are (16)% and (18)% respecttively, while these values decreases when gate slope increases opposite flow direction and the lower lip is horizontal these decreases are (13)% and (11)% respectively. The values of coefficient of velocity (Cv) remain constant and don’t effect with changes of gate slope or gate lip.
