Effect of Negative Slope, Bed Roughness and Positive Step on Velocity Profile and Pressure Oscillations of Hydraulic Jump

Pourabdollah, Nahid; Heidarpour, Manouchehr; Abedi-Koupai, Jahangir; Mohamadzadeh Habili, Jahanshir

doi:10.22055/jise.2018.23313.1657

Effect of Negative Slope, Bed Roughness and Positive Step on Velocity Profile and Pressure Oscillations of Hydraulic Jump

Document Type : Research Paper

Authors

Nahid Pourabdollah ¹

Manouchehr Heidarpour ²

Jahangir Abedi-Koupai ²

Jahanshir Mohamadzadeh Habili ³

¹ PhD Student, Water Engineering Department, Isfahan University of Technology, Iran

² Professor, Water Engineering Department, Isfahan University of Technology, Iran.

³ Assistant Professor, Water Engineering Department, Shiraz University, Iran.

10.22055/jise.2018.23313.1657

Abstract

The control of speed and pressure oscillations along the stream, as two critical parameters in designing hydraulic systems, is vital since they have to be set within an acceptable range in order to prevent damages to hydraulic structures. Ead and Rajaratnam (2002) studied the hydraulic jump characteristics on the corrugated bed and calculated the thickness of dimensionless boundary layer to be 0.45. Pourabdollah et al. (2015) investigated the effect of roughness and adverse slope of the bed on the velocity profile and determined the mean shear force coefficient to be 11.5 times more than that of the classical condition. Fiorotto and Rinaldo (1992) stated that in hydraulic jump the pressure is oscillating around the mean pressure value, which is almost equal to piezometric head at each point. Also Lopardo and Solari (1980) determined the pressure oscillations equal to 0.084 for hydraulic jump at downstream of valve. Accordingly, although various studies have been carried out on hydraulic jump characteristics under different conditions, the simultaneous effect of end positive step, bed roughness and adverse slope on hydraulic jump characteristics have not yet been explored. Therefore, the aim of this study was to investigate the velocity profiles, flow surface and pressure oscillations in hydraulic jump within the stilling basin at defined conditions.

Keywords

Boundary Layer Thickness

Standard Deviation

Shear Stress

Stilling Basin

20.1001.1.25885952.1399.43.1.13.3

Subjects

Hydraulic

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