Simulations of Suspended Sediment Transport Using Low-Reynolds-Number Turbulence Models with a Unified Mesh

Abstract

This paper presents the application of a computationally convenient and physically consistent numerical approach to specify boundary conditions for suspended sediment (SS) with low-Reynolds-number (LRN) turbulence models. This new approach is attractive when the turbulence model equations need to be integrated all the way to the wall without the use of wall functions. A previous paper that discussed the case of using wall functions presented a way to link the bed boundary and a reference height at which many empirical suspended sediment entrainment laws specify a reference concentration (entrainment capacity). This paper is a follow-up to demonstrate a similar approach when LRN models are used. The treatment method with LRN models has been proposed before based on the near-wall turbulent-flow structure. The governing equation for SS was integrated between reference height and wall to derive the new wall boundary conditions. Such an approach eliminates the need for ad hoc treatments of the gap in many sediment transport models. Two applications of the new approach are demonstrated. The results of two examples compare well with experiments and demonstrate the applicability of the new method to more realistic applications.