Critical Submergence of Rectangular Vertical Intakes for Non-axial Flow Condition
Authors :- Sharma, H.; Shrimali, Y.
Publication :- Proceedings of Fluid Mechanics and Fluid Power (FMFP) 2023, Vol. 3. FMFP 2023. Lecture Notes in Mechanical Engineering. Springer, 2025
Since past years, the study of formation of free surface vortex at intake of hydropower plants has been a trendy and interesting subject among engineers and researchers. The one of the important and main problem encountered in hydraulic engineering is air entrainment by means of formation of free air-core vortex at water intake pipe when the submergence over the intake is not enough. Thus, in order to prevent the formation of vortex over intake mouth, a minimum submergence has to be kept over it, which is called as critical submergence. Numbers of formulae are present which predict the critical submergence for vertical intakes for axial flow condition but study is required on how critical submergence is affected by flow non-axiality. In present study, a potential solution was developed for critical submergence by combining the inclined uniform flow and point sink flow. It was observed that in case of non-axial flow, critical submergence required was more than what is required with the axial flow condition. The derived analytical equation of circular intake predicts the critical submergence within the error margin of ±20%. Also in the present study, the regression analysis was performed to propose a functional relationship for prediction of critical submergence for non-axial flow.