MODELING OF ONE-DIMENSIONAL UNSTEADY OPEN CHANNEL FLOWS IN INTERACTION WITH RESERVOIRS, DAMS AND HYDROPOWER PLANT OBJECTS
N. Grujović, D. Divac, B. Stojanović, Z. Stojanović, N. Milivojević
Abstract
A number of existing software solutions are used to model one-dimensional unsteady openchannel
flow using the standard boundary and initial conditions. Internal boundary conditions
are two flow trajectories, related by special conditions and each is associated with two
equations describing the water flow. The special conditions include the matrix formulation of
limitations that apply to the flow inside the two connected trajectories. Branching, pipe joints
and flow over the weir are some of the modeling tasks usually solved. This paper presents the
algorithms used for the solution of the complex case of hydropower plant objects as internal
boundary cases. The complexity of the problem lies in the fact that the hydropower plant is
managed according to the electricity generation demand which is dependent both upon the
upstream and downstream water levels, as well as the discharge. Since all state values are
coupled and determined as system solutions, the algorithm leads to an iterative procedure of
solving a system of non-linear equations. Software used in solving the standard, complete,
dynamic equations of flow in one-dimensional unsteady open channel flow and through the
control structures, was adopted as the foundation applied in simulation of the “Iron Gate”
(“Đerdap” in Serbian; “Portile de Fier” in Romanian) system, with detailed modeling of three
objects of the hydropower plants “Iron Gate 1”, “Iron Gate 2” and “Gogoš”.
