Author(s): How Tion Puay; Takashi Hosoda
Linked Author(s): How Tion Puay, Takashi Hosoda
Keywords: Open channel flow; Super-critical flow; Abrupt expansion flow; Method of Characteristic; Self-similarity
Abstract: This paper describes some of the fundamental characteristics of super-critical flow discharged from an abrupt expansion structure. The flow structure near the abrupt expansion is studied by dividing the flow into inertia-pressure flow region and shear stress-pressure flow region. The inertia-pressure flow region is a region where the flow is under inertia and pressure equilibrium. On the other hand, the shear stress-pressure flow region is the region where the flow is governed by the bed shear stress and pressure equilibrium. Firstly, the inertia-pressure flow region which is situated near the abrupt expansion is studied by using the method of characteristic (MOC). Flow characteristics such as the expansion angle of the zero-depth and characteristic flow zone are shown. Further downstream, where the shear stress-pressure flow region exists, analysis based on the assumption of self-similarity of hydraulics parameter reveals characteristic exponents for the attenuation of flow along center line when travelling downstream. Based on the same self-similarity assumption, the lateral flow profile is also derived for this region. Findings in both inertia-pressure and shear stress-pressure flow regions are verified with depth-averaged numerical model.