Define Viscosity Sedimentology

Sediment transport models are crucial tools used to understand and predict the behavior of sediment-laden flows in various environments. One such model is FLOW-3D's Sediment Transport model, which utilizes a combination of numerical methods and physical processes to simulate the movement of sediment particles. In this article, we will delve into the details of viscosity sedimentology as it pertains to this model.

The Sediment Transport model solves a transport equation to calculate the suspended sediment concentration in each cell. This concentration is assumed to be uniform within a given cell and is coupled with the fluid cell density and viscosity. The suspended sediment is represented as a scalar mass concentration in the fluid, allowing for the simulation of both packed bed and suspended states.

Bed shear stress is evaluated using the standard wall function, taking into account bed surface roughness that is proportional to the median grain size. This is critical in determining the bedload transport rates and entrainment rates in 3D turbulent flows. The location, orientation, and area of the bed interface are calculated in mesh cells containing the bed interface, providing valuable information about the sediment's behavior.

The settling velocity of grains is calculated using Soulsby (1997), while the lifting velocity of grains in entrainment is determined by the equation of Winterwerp et al. A sub-mesh method is employed to determine the amount of grains moving from one mesh cell to another, allowing for a more accurate representation of sediment transport.

The model calculates bedload transport rates using equations such as Meyer-Peter Müller (1948), Nielsen (1992), or Van Rijn (1984). These processes include bedload transport, entrainment, and deposition, which are all critical in understanding the morphological changes that occur in sediment-laden flows. The relative rates of entrainment and packing control the exchange of sediment mass between the packed bed and suspended states.

In conclusion, viscosity sedimentology is a complex field that requires a deep understanding of the physical processes involved in sediment transport. FLOW-3D's Sediment Transport model provides a powerful tool for simulating these processes, allowing researchers to better understand and predict the behavior of sediment-laden flows in various environments.

Define viscosity sedimentology