Document Type : Research Paper
Authors
1 Faculty of Civil Engineering, Jundi Shapur University of Technology, Dezful, Iran
2 Master Graduated, College of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran
3 Instructor, College of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran
4 Associate Professor, College of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran
Abstract
A critical depth of submergence induces vortex formation around the intake inlet. Previous studies suggest inflow threshold points around the intake's inlet can be approximated as a spherical shape. The characteristics of this sphere are influenced by the approach flow velocity V, the intake's location relative to the reservoir sidewall, and boundary friction effects. This article investigates flow patterns around vertical circular intakes with sharp-edge inlets through physical modeling and numerical simulation. Various scenarios were created by varying the intake's internal diameter and height from the reservoir bottom. Hydraulic analyses of flow around a critical sphere were conducted to evaluate the hydraulic characteristics in the area of the Critical Spherical Sink Surface (CSSS). The results revealed that hydraulic properties around the intake inlet, defined using dimensionless parameters such as Froude, Reynolds, Weber, and Kolf numbers, change with variations in the internal diameter of the inlet. Specifically, maximum velocity at the boundary of the spherical sink surface decreases towards zero as flow approaches the reservoir sidewall. A sensitivity analysis on the relative critical submergence depth (Scr/D) showed that Reynolds and Froude numbers exhibit higher sensitivity prior to reaching critical depth compared to Weber and Kolf numbers. Additionally, for relative critical submergence depths greater than 4.7 and relative velocities exceeding 182, all dimensionless parameters significantly influence air absorption. Although incipient limit values of Froude, Reynolds, Weber, and Kolf numbers vary with flow conditions, values for (Scr/D) incipient limit curves are dependent on these dimensionless numbers, while those below are independent.
Keywords
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