Author(s): Gurugubelli Yatirajulu; Laxman V. Rathod; P. V Timbadiya And Bandita Barman

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Keywords: Symmetric sinuous channel; Bed shear stress; Turbulent kinetic energy method; Modified turbulent kinetic energy method; Quadrant analysis

Abstract: Flow through bends is complex where erosion and deposition is a continuous process in the alluvial channels. In the current study, an attempt is made to understand the flow behavior in an asymmetric sinuous channel bend. Experiments were performed by developing a physical model in a laboratory River Tray having sinuosity of 1.23 with rigid banks and a mobile uniform sand bed (particle size (d50) = 1.30 mm and geometric standard deviation (σg) = 1.21). Three-dimensional instantaneous flow velocity is measured using the Acoustic Doppler Vectrino Profiler (ADVP) at the apex of the bend. Estimating bed shear stress (BSS) is particularly challenging in flow through bends. BSS is computed using turbulent kinetic energy (TKE) and modified TKE methods. The modified TKE method was more appropriate for BSS estimation than the TKE method. The variation of TKE at the inner bank follows the pattern of the velocity profile, whereas the center and outer points of the bend show higher magnitudes at the near-bed region. Study of quadrant analysis demonstrates that ejection and sweep events show maximum positive magnitude and are responsible for the movement of sediments. The magnitude of BSS computed using both methods shows higher values at the inner and center of the bend, whereas the lowest values at the outer bank of the bend. The findings of the current study offer recommendations for the experimental assessment of BSS in a complicated flow field.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1836-cd

Year: 2025