Abstract
The hysteresis phemena which can occur in transition between gated flow and free flow are experimentally clarified, and the profile and the fluctuation of water surface and the velocity profile under the relationship among the water hight, the gate opening and the discharge is described as the discontinuous condition in transition. And then, the unsteady discharge characteristics in transition are experimentally analyzed, and the validiity of the propose equation is confirmed though the comparision with the discharge based on the velocity. In addition, it appears that the numerical simulation model using the incompressible fluid analysis and VOF can simulate the hysteresis phenomena in transition.
