Armoring and exposure effects on the wave-driven sediment transport

Entrainment and Transport of Well‐Sorted and Mixed Sediment Under Wave Motion

“…12 of 19 (Rafati et al, 2020) (see Figures 6b, 6c, 6j, and 6k). The armoring effect may be responsible for the negligible phase lag effects observed in the BM distribution during the flow reversal (Figures 5e and 6l).…”

“…The average drag force is calculated by averaging the drag forces on the particles within a fluid cell. To account for the turbulence‐induced particle suspension, the eddy interaction model (Graham & James, 1996) was used which previously showed good skill in modeling the turbulent suspension in steady (Cheng et al., 2018) and oscillatory (Rafati et al., 2020) sheet flow simulations. The fluid shear stress is calculated as the sum of the viscous stress and turbulent Reynolds stress, where the Reynolds stress is calculated based on eddy viscosity using k‐ε model.…”

“…The coupling between fluid and particle phase solvers is accomplished by CFDEM (Goniva et al, 2012). A brief overview of the governing equations and the closure models is given below (additional details in Cheng et al (2018) and Rafati et al (2020)).…”

“…The bottom and the top boundaries were assigned as no-slip wall and the shear-free symmetric boundary, respectively. An immobile sediment layer at the bottom of the model domain is established by placing very dense particles (density of 26,500 kg/m 3 ) with a diameter twice the median grain diameter of the mixture (Rafati et al, 2020). The domain size was chosen following Rafati et al (2020) to be l x = 20d 50 and l y = 10d 50 , where l x and l y represent the domain length in streamwise and spanwise directions, respectively.…”

“…Depending on the wave intensity, fine and coarse sediment particles respond differently to the flow field as they transport and settle in different locations in the cross‐shore direction; causing well‐sorted and mixed sediment size distributions locally (Huisman et al., 2016; Kaczmarek et al., 2004; Prodger et al., 2016; Stauble, 1992). In the past two decades, two‐phase Eulerian‐Lagrangian models have been used to simulate the sediment beds consisting of non‐uniform sediment particle sizes under wave motions (Calantoni & Thaxton, 2008; Drake & Calantoni, 2001; Finn et al., 2016; Rafati et al., 2020). These studies showed that sediment beds consisting of uniform and non‐uniform sediments respond differently to the wave‐induced flows due to the sorting processes (Calantoni & Thaxton, 2008; Harada & Gotoh, 2008; Hassan & Ribberink, 2005; Rafati et al., 2020).…”