ANALYSIS OF FLOWS THROUGH AND OVER A RUBBLE MOUND WEIR AND CLASSIFICATION OF FLOW REGIME

Abstract

 A one-dimensional two-layer model was developed in order to examine the hydrodynamics of rubble mound weirs. First, depending on the water depth relative to the weir height, the flow was classified into three regimes: (a) “Regime-S, ” in which the weir was submerged along the whole reach, (b) “Regime-P, ” in which the weir was submerged only in the upstream reach, and (c) “Regime-E, ” where the weir was emerged in the whole reach. Second, each regime was further grouped under two sub-categories: (i) “B-flow” that is controlled by backwater from downstream of the weir, and (ii) “C-flow” that is controlled by a critical hydraulic depth appearing at the weir exit. Theoretical solutions for water surface profile and discharge rating curve were obtained for the six flow regimes and were validated in comparison with experimental data.