| The water-release tower was extensive applied in silt reservoir replaces lie pipe as a shaft water-release structures because of its merits. These merits include the stabilization of leakage flow, the good capability of defends fill up, the long life span, the simple structure, the lesser cost, easy to manage and so on. The relevant data show that our country will increase the construction of dam project in the future, and propose to construct about 16.3 ten thousand seats. In other words, more and more water-release tower will be extensive applied. However, the research on hydraulic characteristic of the water-release tower is rather less, so the engineers couldn't get enough detailed data as reference, as a result, the engineers made unnecessary wastes and even hidden trouble was existed during the design process.This paper is on the basic of the seven reservoirs project of JINGBIAN county which is planned to remove danger and reinforce, meantime the hydraulic characteristic of water-release tower is studied through model experimentation. This experimentation chose five infall in different height of the tower, from bottom to top, which are bottom orifice, upside one orifice, upside two orifice, upside three orifice and upside four orifice. The key results of this model experiment are as follows:1) In the experiment process, we could fin out some phenomena by observing the flow condition in different height and angle. We could see that the infall were all freedom leakage flow when the infall and outlet' axis angle was zero degree, hower, when the infall and outlet' axis angle was thirty degree, sixty degree, ninety degree. However, when the bottom infall was submerged but the upside infall were still freedom leakage flow.2) The change of the infall's height and angle made a little influence on leakage flow, but the change of the bottom infall's angle made a lot influence on leakage flow. Then the submergecoefficientσs about the bottom infall could be found out. The relation ship how theσs changed with h-s/H and angle, and the empirical computing formula of leakage flow with different flow condition could be got through test data fitting. 3) Good comparability is lied in equal impact pressure of the vertical axis when y/b0≥-1.8, which is closed to normal distribution, namely: ps /Pmax=exp(-0.5(y//b0)2).4) The preponderant frequency of the tower's wall and bottom centralized within 0～2Hz, and the peak value frequency centralized within 0～1Hz, which are all belonged to low frequency shake, therefore, the vibration wreck phenomenon couldn't happen under the pulse strength.5) The total system ratio of damping in energy was between 84% and 90%, which can satisfy the request of energy dissipation in actual project.6)The ideal size of dissipation well should be: H0/D0=0.77, D/D0=1.00 or H0/D0=0.50, D/D0=1.33. |
