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      https://www.ias.ac.in/article/fulltext/jess/129/0099

    • Keywords

       

      Wave-current; cohesive-sediment; bank erosion; quadrant decomposition; spectral analysis

    • Abstract

       

      The effect of hydrodynamic forces due to combined action of surface waves and current on the riverbank is critical to understand sediment entrainment, transport and bank line retreatment process. In understanding the temporal effect of turbulent structures under induced wave-current Cow, a series of laboratory experiments were carried out. Micro-Acoustic Doppler Velocimeter (ADV) and Ultrasonic Ranging System (URS) were used simultaneously for the measurement of velocity fluctuations and bank undercut depth increment. Modulation of the turbulent flow characteristics and the benefaction of turbulent bursting structures at the initiation of erosion process and before the failure of the cohesive bank due to undercut progression are discussed. The results show that velocity and Reynolds shear stress have direct dependence on the size and rate of the entrainment of cohesive aggregates from bank face. The effect of wave-current motion leads to an increase in shear stress at the lateral bank giving rise to erosion and transportation of sediment particles/aggregates. Quadrant analysis of the random velocity fluctuation under wave-current flow at the initiation of erosion process shows strong presence of ejection and sweep events. Findings from the present study may provide a better understanding on the design of cohesive bank erosion control measures.

    • Author Affiliations

       

      VIKAS KUMAR DAS1 SAYAHNYA ROY1 KRISHNENDU BARMAN2 SUSANTA CHAUDHURI3 KOUSTUV DEBNATH1

      1. Fluid Mechanics and Hydraulic Laboratory (FMHL), Department of Aerospace Engineering and Applied Mechanics, Indian Institute of Engineering Science and Technology (IIEST), Shibpur 711 103, India.
      2. Department of Applied Mathematics with Oceanology and Computer Programming, Vidyasagar University, Midnapore 721 102, India.
      3. Department of Geological Sciences, Jadavpur University, Kolkata 700 032, India.
    • Dates

       
  • Journal of Earth System Science | News

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