<abstract xmlns="http://www.w3.org/1999/xhtml"><p> Traditional depth-averaged morphodynamic models for turbidity currents usually focus on the propagation of currents after plunging. However, owing to the unsteady characteristic of the plunge point locations and the tough conditions of field measurement within the plunge zone in a reservoir, it is difficult in practice to directly provide upstream boundary conditions for these models. A one-dimensional (1D) morphodynamic model coupling open-channel flow and turbidity current in a reservoir was proposed to simulate the whole processes of turbidity current evolution, from formation and propagation to recession. The 1D governing equations adopted are applicable to open-channel flows and turbidity currents over a mobile bed with irregular cross-section geometry. The coupled solution is obtained by a two-step calculation mode which alternates the calculations of open-channel flow and turbidity current, and a plunge criterion is used to determine the location of the upstream boundary for the turbidity current, and to specify the corresponding boundary conditions. This calculation mode leads to consecutive predictions of the hydrodynamic and morphological factors, from the open-channel reach to the turbidity current reach. Turbidity current events in two laboratory experiments with different set-ups were used to test the capabilities of the proposed model, with the effect of free-surface gradient also being investigated. A field-scale application of the coupled model was conducted to simulate two turbidity current events occurring in the Sanmenxia Reservoir, and the method for calculating the limiting height of aspiration was adopted to estimate the outflow discharge after the turbidity currents arrived in front of the dam. The predicted plunge locations and arrival times at different cross-sections were in agreement with the measurements. Moreover, the calculated interface evolution processes and the sediment delivery ratios also agreed generally with the observed results. Therefore, the 1D morphodynamic model proposed herein can help to select the design capacity of the outlets, and optimize the procedure for sediment release in reservoirs.</p></abstract>

Traditional depth-averaged morphodynamic models for turbidity currents usually focus on the propagation of currents after plunging. However, owing to the unsteady characteristic of the plunge point locations and the tough conditions of field measurement within the plunge zone in a reservoir, it is difficult in practice to directly provide upstream boundary conditions for these models. A one-dimensional (1D) morphodynamic model coupling open-channel flow and turbidity current in a reservoir was proposed to simulate the whole processes of turbidity current evolution, from formation and propagation to recession. The 1D governing equations adopted are applicable to open-channel flows and turbidity currents over a mobile bed with irregular cross-section geometry. The coupled solution is obtained by a two-step calculation mode which alternates the calculations of open-channel flow and turbidity current, and a plunge criterion is used to determine the location of the upstream boundary for the turbidity current, and to specify the corresponding boundary conditions. This calculation mode leads to consecutive predictions of the hydrodynamic and morphological factors, from the open-channel reach to the turbidity current reach. Turbidity current events in two laboratory experiments with different set-ups were used to test the capabilities of the proposed model, with the effect of free-surface gradient also being investigated. A field-scale application of the coupled model was conducted to simulate two turbidity current events occurring in the Sanmenxia Reservoir, and the method for calculating the limiting height of aspiration was adopted to estimate the outflow discharge after the turbidity currents arrived in front of the dam. The predicted plunge locations and arrival times at different cross-sections were in agreement with the measurements. Moreover, the calculated interface evolution processes and the sediment delivery ratios also agreed generally with the observed results. Therefore, the 1D morphodynamic model proposed herein can help to select the design capacity of the outlets, and optimize the procedure for sediment release in reservoirs.

One-dimensional morphodynamic model coupling open-channel flow and turbidity current in reservoir

State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, 430072 Wuhan,

Yellow River Institute of Hydraulic Research, YRCC, 450003 Zhengzhou,

Journal of Hydrology and Hydromechanics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Traditional depth-averaged morphodynamic models for turbidity currents usually focus on the propagation of currents after plunging. However, owing to the...

One-dimensional morphodynamic model coupling open-channel flow and turbidity current in reservoir

Published Online: Dec 08, 2016

Page range: 68 - 79

Received: May 19, 2016

Accepted: Jul 26, 2016

DOI: https://doi.org/10.1515/johh-2016-0046

Keywords
Turbidity current, Open-channel flow, Coupled solution, Morphodynamic model, Plunge point, Reservoir

© 2016

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

One-dimensional morphodynamic model coupling open-channel flow and turbidity current in reservoir

Published Online: Dec 08, 2016

Page range: 68 - 79

Received: May 19, 2016

Accepted: Jul 26, 2016

DOI: https://doi.org/10.1515/johh-2016-0046

KeywordsTurbidity current, Open-channel flow, Coupled solution, Morphodynamic model, Plunge point, Reservoir

© 2016

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
Turbidity current, Open-channel flow, Coupled solution, Morphodynamic model, Plunge point, Reservoir