title: Verification of equations for incipient motion studies for a rigid rectangular channel.
abstract: 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.
authors.affiliation: River Engineering and Urban Drainage Research Centre (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. bhjcharles@feng.unimas.my
authors.forename: Charles Hin Joo
authors.initials: CH
authors.lastname: Bong
authors.forename: Tze Liang
authors.initials: TL
authors.lastname: Lau
authors.forename: Aminuddin Ab
authors.initials: AA
authors.lastname: Ghani
mesh_terms: D004323:Drainage, Sanitary; D019015:Geologic Sediments / Q000737:chemistry*; D008962:Models, Theoretical; D009038:Motion; D015203:Reproducibility of Results