Author(s): S. Haun; L. E. Hoven; N. R. B. Olsen; C. R. Rodriguez Meza; L. Lizano
Linked Author(s):
Keywords: Numerical modelling; RANS model; Sediment deposition; Reservoir flushing
Abstract: The current study focuses on computing the sediment deposition and the flushing process in a hydropower reservoir with a three-dimensional numerical model. The applied numerical model (SSIIM 2) solves the Reynolds-averaged Navier-Stokes equations in three dimensions. The turbulence is predicted by the standard k-ε model and the pressure is calculated according to the SIMPLE method. An iterative free water surface algorithm is used which makes it possible to use large time steps. The program uses an adaptive and unstructured grid, which moves with the time-dependent changes in the water and bed levels. The model is tested on the basis of the data from the Angostura reservoir in Costa Rica. Results from the numerical simulation of the deposition and the flushing are presented and compared with bathymetry data of the bed level from the prototype. The computations show that the deposition is easier to model than the flushing. The results for the location of deposition agree better with the measured pattern than the prediction of the erosion of the flushing calculation.
Year: 2011