TY - JOUR ID - 3852 TI - Numerical Investigation of Hydraulic Characteristics of Vertical Drops with Screens and Gradually Wall Expanding JO - Amirkabir Journal of Civil Engineering JA - CEEJ LA - en SN - 2588-297X AU - Nayebzadeh, Behnam AU - Lotfollahi-yaghin, Mohammad Ali AU - Daneshfaraz, Rasoul AD - PhD civil student in Tabriz University AD - Professor, ph.d, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran AD - Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran. Y1 - 2021 PY - 2021 VL - 53 IS - 8 SP - 3221 EP - 3238 KW - Vertical drop KW - Porosity ratio KW - Turbulence models KW - Gradually wall expanding KW - Flow-3D DO - 10.22060/ceej.2020.17779.6671 N2 - In the present study, the hydraulic characteristics of vertical drops with screens and the gradual wall expanding downstream using FLOW-3D software are investigated. For this purpose, two porosity ratios of the screens of 40 and 50%, 5 gradually expanding with 3 vertical drop heights in the specified discharge range were used. It was found that the numerical results are closer to the experimental results with the RNG turbulence model than k-ε. By increasing the drop height, the ΔE/E0 due to the jet floor impact intensity increased and yp/P value decreased. The maximum ΔE/E0 for 25 cm height was 51.60% and the lowest for 15 cm was 44.25%. For a constant drop height with increasing discharge, the ΔE/E0 decreased and yp/P increased. The gradually wall expanding causes turbulence on the edges and a non-uniform distribution of yd/P and by increasing yp/P and yd/P, it caused a 25% increase in ΔE/E0. The presence of screens increased yp/P, yd/P, and ΔE/E0 by 44%. The simultaneous use of gradually walls expanding and screens caused a 46% increase in ΔE/E0 and a decrease in yp/P and yd/P values. It was shown that the contribution of screens is greater than the gradually wall expanding, with their simultaneous application increasing ΔE/E0 up to 33.5%. UR - https://ceej.aut.ac.ir/article_3852.html L1 - https://ceej.aut.ac.ir/article_3852_265939ccf2a09b5c88804ffbe5e35c56.pdf ER -