Influence of Vertical Force on Shields’ Curve and Its Extension in Rapidly Varied Flow
Muhammad Zain Bin Riaz,
Umair Iqbal,
Huda Zain,
Shu-Qing Yang,
Muttucumaru Sivakumar,
Rong Ji,
Muhammad Naveed Anjum
Affiliations
Muhammad Zain Bin Riaz
School of Civil, Mining, Environmental and Architectural Engineering (SCMEA), University of Wollongong, Wollongong, NSW 2522, Australia
Umair Iqbal
University of Newcastle, Newcastle, NSW 2308, Australia
Huda Zain
Department of Chemical Engineering, Faculty of Chemical, Metallurgical & Polymer Engineering, University of Engineering and Technology, Lahore 54890, Pakistan
Shu-Qing Yang
School of Civil, Mining, Environmental and Architectural Engineering (SCMEA), University of Wollongong, Wollongong, NSW 2522, Australia
Muttucumaru Sivakumar
School of Civil, Mining, Environmental and Architectural Engineering (SCMEA), University of Wollongong, Wollongong, NSW 2522, Australia
Rong Ji
School of Civil, Mining, Environmental and Architectural Engineering (SCMEA), University of Wollongong, Wollongong, NSW 2522, Australia
Muhammad Naveed Anjum
Department of Land and Water Conservation Engineering, Faculty of Agricultural Engineering and Technology, PMAS-Arid Agriculture University, Rawalpindi 46000, Pakistan
Sediment transport is a geophysical phenomenon characterized by the displacement of sediment particles in both the horizontal and vertical directions due to various forces. Most of the sediment transport equations currently used include only parameters related to the horizontal direction. This study measured both instantaneous longitudinal and vertical parameters, i.e., velocities and forces, and found that the magnitude and direction of the vertical force play an important role in sediment incipient motion. An innovative experimental system was developed to investigate the effect of vertical force on incipient motion in rapidly varying flows. A quadrant analysis of the instantaneous measured forces on the critical shear stress was performed. The research revealed that upward positive vertical forces enhance particle mobility, whereas downward negative vertical forces increase particle stability. Novel equations have been developed to represent the influence of vertical forces on sediment transport. A comprehensive critical Shields stress for sediment transport was proposed, extending the Classic Shields diagram to encompass the incipient motion in highly unsteady flows.
