Comparison of depth-averaged concentration and bed load flux sediment transport models of dam-break flow

Journal Article · Thu Dec 21 00:00:00 EST 2017 · Water Science and Engineering

DOI:https://doi.org/10.1016/j.wse.2017.12.006· OSTI ID:1482523

Zhao, Jia-heng ^[1]; Özgen-Xian, Ilhan ^[2]; Liang, Dong-fang ^[3]; Hinkelmann, Reinhard ^[1]

---

1. Technische Univ. Berlin (Germany). Dept. of Civil Engineering
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Technische Univ. Berlin (Germany). Dept. of Civil Engineering
3. Univ. of Cambridge (United Kingdom). Dept. of Engineering

This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms (a depth-averaged concentration flux model), and shallow water equations with a fully coupled Exner equation (a bed load flux model). Both models were discretized using the cell-centered finite volume method, and a second-order Godunov-type scheme was used to solve the equations. The numerical flux was calculated using a Harten, Lax, and van Leer approximate Riemann solver with the contact wave restored (HLLC). A novel slope source term treatment that considers the density change was introduced to the depth-averaged concentration flux model to obtain higher-order accuracy. A source term that accounts for the sediment flux was added to the bed load flux model to reflect the influence of sediment movement on the momentum of the water. In a one-dimensional test case, a sensitivity study on different model parameters was carried out. For the depth-averaged concentration flux model, Manning's coefficient and sediment porosity values showed an almost linear relationship with the bottom change, and for the bed load flux model, the sediment porosity was identified as the most sensitive parameter. The capabilities and limitations of both model concepts are demonstrated in a benchmark experimental test case dealing with dam-break flow over variable bed topography.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1482523
• Journal Information: Water Science and Engineering, Vol. 10, Issue 4; ISSN 1674-2370
• Publisher: Elsevier - Hohai University
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES