Author(s): Ehsan Jafari Nodoushan, Mohanna Tajnesaie, Ahmad Shakibaeinia
Linked Author(s): Ehsan Jafari Nodoushan
Keywords: Mesh-free Lagrangian method, MPS, sediment dynamics, two-phase flow, scour around circular pipes.
Abstract: Mesh-free Lagrangian (particle) methods such as MPS (Moving Particle Semi-implicit) and SPH (Smoothed Particle Hydrodynamics) have proven their capacities in dealing with some the most complex flow systems, especially those with highly distorted and fragmented interfaces. In combination with visco-plastic constitutive relations, these methods can also simulate the solid-liquid multiphase flows, for example in case of sediment-water two phase flow. This provides a unique opportunity for the simulation of the most challenging sediment dynamic problems. Local sediment scours around pipelines, which has many engineering applications, is one of these problems. This paper develops and evaluates a mesh-free Lagrangian model, based on a weakly-compressible version of the MPS method, for 2D modeling of sediment scour around circular pipes. This is a challenging problem for the traditional mesh-based methods due to the highly-dynamic movement of sediments. The flow will be treated as a two-phase system of Newtonian (water) and non-Newtonian (sediment) fluids. A regularized viscoplastic rheological model with a Mohr-Coulomb failure criterion will be used to describe the behavior of sediments. The validation of model results with the available experimental data proves the capability of the developed model for accurate prediction of scour hole under the pipelines
Year: 2017