Verification of equations for incipient motion studies for a rigid rectangular channel

• Main Authors: Bong, Charles Hin Joo, Tze, Liang Lau, Aminuddin, Bin Ab Ghani
• Format: E-Article
• Language: English
• Published: IWA Publishing 2013
• Subjects: TD Environmental technology. Sanitary engineering
• Online Access: http://ir.unimas.my/id/eprint/29999/1/Verification%20of%20equations%20for%20incipient%20motion%20studies%20for%20a%20rigid%20rectangular%20channel%20-%20Copy.pdf; http://ir.unimas.my/id/eprint/29999/; https://iwaponline.com/wst/article/67/2/395/14886/Verification-of-equations-for-incipient-motion
• Institution: Universiti Malaysia Sarawak

The current study aims to verify the existing equations for incipient motion for a rigid rectangular channel. Data from experimental work on incipient motion from a rectangular flume with two different widths, namely 0.3 and 0.6 m, were compared with the critical velocity value predicted by the equations of Novak & Nalluri and El-Zaemey. The equation by El-Zaemey performed better with an average discrepancy ratio value of 1.06 compared with the equation by Novak & Nalluri with an average discrepancy ratio value of 0.87. However, as the sediment deposit thickness increased, the equation by El-Zaemey became less accurate. A plot on the Shields Diagram using the experimental data had shown the significant effect of the sediment deposit thickness where, as the deposit becomes thicker, the dimensionless shear stress θ value also increased. A new equation had been proposed by incorporating the sediment deposit thickness. The new equation gave improved prediction with an average discrepancy ratio value of 1.02.