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Corresponding Author

Attia, M.

Subject Area

Civil and Environmental Engineering

Article Type

Original Study

Abstract

In this research paper, an experimental investigation was carried to study the turbulent structure and flow characteristics through inclined finite depression in sloping rectangular channel of constant width using Laser Doppler Anemometer (LDA). To study the turbulent structure , precise and accurate measurements of the mean and fluctuating flow quantities such as turbulence intensity components (0. and v/U) and mean velocity components (ūU, and /U.). The measurements were carried out along the flow depth at different cross-sections within and downstream of the finite depression. Also, the measurements were conducted at different relative height b/b and different finite depression angle 0 in the longitudinal direction along the centerline and across the finite depression at different locations to assess the variation of the maximum turbulence intensities (Umar, and v .). Experiments were conducted under different variables such as, bed slope , relative heights , relative length of finite depression to study the variation of the energy loss with the main parameters affecting the finite depression in sloping channel . The energy loss through the finite depression length was computed and correlated to the relevant parameters. These parameters include the bed slope , the upstream Froude number, the relative height ratio , the finite depression angle, the relative length ratio and the upstream head ratio . The effect of all these parameters on the energy loss through the finite depression were analyzed and discussed , Non – dimensional design curves were provided to relate the flow characteristics. The results show that, the turbulence intensities úm . and Vmax/U. along the centerline beyond x/h > 6.1, úmax/U, and v'maxUwere always higher in the case of 90° flow and lower for gradual 15° flow. This trend was exactly opposite as observed for wh<3.2, where the turbulence intensity was maximum for the 150 flow and minimum for the 90° flow, and the maximun of NU and vimax WUoccurs in the intermediate zone 3.2 0.3.

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