Mechanism of amplifications of hyper-concentrated flood and criterion of its occurrence in the Lower Yellow River

Yuanjian Wang, Enhui Jiang

Tuesday 30 june 2015

17:54 - 17:57h at Mississippi (level 1)

Themes: (T) Sediment management and morphodynamics, (ST) Sediment transport mechanisms and modelling, Poster pitches

Parallel session: Poster pitches: 7A. Sediment - Erosion

Phenomenon of amplifications of hyper-concentrated flood occur in the Lower Yellow River at times. This study took the phenomenon as a result of flow instability. Derived from the analysis on the characteristic of wave equations, mechanism and criterion of flood amplifications were explored in this paper. The results show that: if velocity of dynamic waves is greater than that of kinetic waves, spreading velocity back of wave will be greater than that in front, flood amplifications occur. In the condition of clear water, the criterion of flood amplifications is Fr>1.5(Fr is the froude number); While for hyper-concentrated flood, as the structural change of the resistance equation, the criterion will be changed to Fr