TURBULENCE-RESOLVING NUMERICAL SIMULATION OF FINE SEDIMENT TRANSPORT OVER BEDFORMS
AbstractWave-supported gravity currents in turbulent wave bottom boundary layer (WBBL) are one of the most important processes causing cross-continental shelf sediment transport. The high numerical accuracy 3D numerical model has been used to investigate the fine sediment transport in the WBBL and several different transport modes have been found due to sedimentinduced density stratification (Ozdemir et al., 2010; Cheng et al., 2015). However, laboratory experiments suggest the presence of a small amount of sand fraction and the formation of ripple bed alter the structure of WBBL significantly (Hooshmand, et al., 2015). The purpose of this study is to understand the interplay of fine sand, bedforms, and sediment-induced density stratification in determining the transport modes of fine sediments in WBBL through turbulence-resolving numerical simulations.
Balachandar, Eaton (2010): Turbulent dispersed multiphase flow, Ann. Rev. Fluid Mech., 42, 111-133.
Cheng, Yu, Hsu, Ozdemir, Balachandar (2015): On the transport modes of fine sediment in the wave boundary layer due to resuspension/deposition, J. Geophys. Res.: Oceans, 120, 1918-1936.
Yang, Shen (2011): Simulation of viscous flows with undulatory boundaries. Part I: Basic solver, J. Comp. Phys., 230, 5488-5509.
Hooshmand, Horner-Devine, Lamb (2015): Structure of turbulence and sediment stratification in wave-supported mud layers, J. Geophys. Res.: Oceans, 120, 2430-2448.
Hudson, Dykhno, Hanratty (1996): Turbulence production in flow over a wavy wall, Exp. Fluids, 20, 257.
Ozdemir, Hsu, Balachandar (2010): A numerical investigation of fine particle laden flow in an oscillatory channel: the role of particle-induced density stratification, J. Fluid Mech., 665, 1-45.
Hir, Cayocca, Waeles (2011): Dynamics of sand and mud mixtures: A multiprocess-based modelling strategy, Cont. Shelf Res, 31, S135-S149.
Soulsby, Manning, Spearman, Whitehouse (2013): Settling velocity and mass settling flux of flocculated estuarine sediments, Mar. Geo., 339,1-12.