Abstract
The purpose of this paper is to analyze theoretically and experimentally the initial motion of negative surge caused by the opening or closing of a gate.
Assuming that the downstream side of the gate is free of water, four types of generating? conditions of negative surges are studied in case of a horizontal channel with a nonviscous flow:
Type A, a sudden full opening of a gate;
Type B, a sudden partial opening of a gate;
Type C, slow opening of a gate and
Type D, a sudden full opening of a gate at the top of a weir.
In the case of Type A, where the so-called Dam Break Wave is produced, Rittter has already obtained the theoretical solution.
But a further analysis is made here for the purpose of comparing it with other types of negative surges.
For Type B, formula (16) is obtained.
ΔH=0.84D…(16)
where ΔH is the height of the surge and D is the degree of opening of a gate.
For Type C, the shape of the water surface and the velocity distribution of the surge can be expressed by formulas (29) and (31), which are considered to involve Ritter's solution.
For Type D, z/H is found to play a most significant role in forming the flow state after the negative surge passes the weir, where z is the height of the weir and H is the initial depth of the water.
