Thermodynamic Analysis of Sediment Transport in Multiphase Systems

Abstract:

Understanding and mathematically modelling sediment transport is crucial to the development and planning of riverine, coastal, and hydraulic infrastructure. However, most macroscopic models which have been proposed fail to fully account for the second law of thermodynamics, a condition which, while not sufficient, is necessary. Applying the framework of thermodynamically constrained averaging theory, an entropy inequality is used to evaluate many two and three phase closure relations for the momentum transfer between phases. This entropy inequality is then utilized to derive a thermodynamically consistent closure relation. Many proposed closure relations have been found to violate this necessary condition. We propose a relation which will not and validate this with simulations.