Document Type : Original Article
Authors
- Farinaz Shoja Talatapeh 1
- Davood Farsadizadeh 2
- Ali Hosseinzadeh Dalir 3
- Javad Behmanesh 4
- Mohammad Reza Nikpour 5
1 Departrment of water engineering, University of Tabriz, Tabriz
2 Professor, Department of Water Engineering, University of Tabriz, Tabriz, Iran
3 Professor, Department of Water engineering, University of Tabriz
4 Professor, Department of Water engineering, University of Urmia
5 Assistant Professor, Department of Water Engineering, University of Mohaghegh Ardabili, Ardabil
Abstract
In the present research, height and velocity of shock waves in contractions of open-channel with trapezoidal and rectangular sections was investigated using experimental models. For this purpose, length of transition (0.5m), convergence ratio (1/2, 1/3 and 1/4) and side slope angle (45o, 60o, 70o and 90o) were considered as geometric variables of the experiments. Also 4 Froude number was assumed as a hydraulic variable of the experiments in the range of 3.25-9.23. Analysis of Free surface & velocity profiles of shock waves showed that in general, the increasing of side slope angle of the transition wall, reduction of convergence ratio, and increasing of Froude number have a direct relationship with the increasing height and velocity of shock waves. The results showed that in the contraction with trapezoidal section with the convergence ratio (1/2) and side slope angle (45o, 60o and 70o) compared with rectangular cross-section, on average maximum height of shock waves respectively decreased to: 59.34, 44.27 and 24.04. In the same condition the maximum velocity of shock waves respectively decreased to: 37.51, 25.23 and 14.67. As Executive channels mainly with a trapezoidal cross-section are building and operating, so the findings of this study can be very useful for design engineers.
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