Numerical Investigation of Hydrodynamic Interaction of Outlet Discharge Process in Stratified Reservoirs

Document Type : Research Paper


1 Assistant Professor, Hydro-Environment Department, Water Research Institute, Ministry of Energy, Tehran, Iran

2 Department of Civil Engineering, Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin, Iran

3 Assistant professor, Civil Engineering Department, Faculty of Engineering, Imam Khomeini International University, Qazvin

4 Hydro-Environment Department, Water Research Institute, Ministry of Energy, Tehran, Iran


The problem of flow discharge from outlet in stratified reservoirs and its interactions in the stratification environment is one of the most important problems in hydraulics of gates and conduits. Investigation and modeling of different behavior of the flow pattern during discharge from the outlet despite stratified reservoir is an objective of this paper. The use of numerical modeling makes it possible to approach optimal management in stratified reservoirs. In this paper, firstly, the evaluation of the numerical model was carried out by the result of a laboratory outlet model in a similar manner. By comparing the results between the two models, the ability of the mathematical model was acceptable. After that, the numerical model was run with six selected flow rates in real scale to investigate the hydrodynamic interaction of the discharge process in the stratified reservoir. According to the numerical results, three modes containing stable, poor and heavy mixing among layers was occurred. The results showed up to discharge rate of 10 CMS (cubic meters per second), only the layer in front of the outlet is evacuated and no mixture is formed among other layers. However, the start of instability and mixing layers found in the discharge rate of 40 CMS and by increasing up to 90 CMS, the intensive mixing among layers was observed and all dense layers were involved in the discharge process. In this case, flow will not feel stratification.


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