Coupled modelling of flow and non-capacity sediment transport in sewer flushing channel

Modelling reservoir sediment flushing through a bottom tunnel with an initially covered intake

“…The computational module for sediment-laden flow in the bottom tunnel is extended from that of Liu et al [40]. The governing equations of the 1D depth-averaged model [40] are derived from fundamental conservation laws for shallow water-sediment flow dynamics, to give:…”

“…open-channel flow pressurized flow A detailed description of the numerical algorithm is given by Liu et al [40], where the hyperbolic system is numerically solved using a shock-capturing finite volume method with inter-cell numerical fluxes computed by the HLLC Riemann solver [46]. 13…”

“…Furthermore, 6 most existing sewer models experience major limitations, through either neglecting mass exchange between flow and bed in the bottom tunnel [38] or assuming the sediment transport is equal to equilibrium capacity [36,39]. Recently, Liu et al [40] proposed a coupled noncapacity model 1D model for resolving the hydro-sediment-morphodynamic processes of sewer flushing. However, this model cannot resolve the complicated physics of hyperconcentrated flows, where interphase and particle-particle interactions prevail [41], that frequently occur during the riverbed collapse process once the gate of the bottom tunnel has been opened [25].…”

“…Besides, interphase and particle-particle interactions prevail as sediment concentration rises. Therefore the resistances for the Newtonian fluid and solid phases are determined by Manning's equation[40] and the Coulomb friction law[42] respectively as follows : bed roughness Manning's coefficient, R is the hydraulic radius of the cross section, , and  is the angle of the bottom bed of tunnel.…”