TY - JOUR T1 - Comparison of Hydraulic Performance of Linear and Nonlinear Piano-Key Weirs in Plan TT - مقایسه عملکرد هیدرولیکی سرریزهای کلیدپیانویی خطی و کلیدپیانویی غیر‌خطی در پلان JF - JSTNAR JO - JSTNAR VL - 23 IS - 3 UR - http://jstnar.iut.ac.ir/article-1-3787-en.html Y1 - 2019 SP - 395 EP - 407 KW - Weir KW - Linear piano key KW - Non-linear piano key KW - FLOW3D KW - Discharge coefficient KW - Numerical modeling N2 - In this research, by using FLOW3D, the performance of non-linear (arced) piano key (PKW-NL) in plan and linear piano key weir (PKW-L), with equal length of weir, was compared. Results showed that nonlinearity of the weir caused 20% increase in the discharge coefficient. Investigating the velocity contours for these two weir models also showed that maximum velocity within the PKW-NL weir structure is about 30% lower than the PKW-L weir. Also, the performance of non-linear piano key weir was evaluated under inward (PKW-IC) and outward (PKW-OC) curvatures to the channel. Results showed that in the case of PKW-IC weir, the discharge coefficient was increased by 8% as compared to the PKW-OC weir. Investigating the pressure contours for these two weir models also shows that the average pressure within the PKW-IC weir structure is about 5% higher than the PKW-OC weir. This increase in pressure leads to a decrease in the speed and better distribution of flow over the weir keys. M3 10.47176/jwss.23.3.34122 ER -