A simplified mathematical model to estimate the erosive capacity of a pulsating laminar muddy flow

ABSTRACT

In this paper, we proposed and validated a simplified mathematical model to estimate the erosive capacity of a muddy laminar flow with roll waves (pulsating effect) on the free surface. From the perspective of applying results in the context of natural disasters (mudflows), the evolution of mean velocity and bottom shear stress in the channel were determined. The proposed model is based on shallow water equations and Herschel-Bulkley rheology as representative of the muds. The model was validated by comparison with results of numerical simulations and experimental data of roll waves generated in a channel. In-depth comparative analyses were made for inferring the erosive capacity of this sort of flow. The obtained results show an increase of erosive capacity (12%) due to the presence of roll waves in relation to the uniform flow’s. Similar values (10%) were found by Ng and Mei (1994) for a more simplified rheology model.

Keywords:
mudflows; non-Newtonian fluid; roll waves; bottom shear stress