Particle Transport in Fluids

Overview and Plans

A Statoil-funded PhD project, bringing together expertise in fluid dynamics, sedimentation, and statistical physics, has resulted in a promising, novel framework for modeling transport of particles in fluids, where particle-level physics can be directly incorporated, and where particles are clustered in lumps to obtain higher computational efficiency than in a pure Lagrangian particle tracking method. The project is now extended for a postdoctoral period of two years for Omar al-Khayat, with the aim of bringing the proof-of-concept 2D framework in Python to three dimensions and high-performance parallel computing. Moreover, the aim is to apply this framework to turbidity currents or particle deposition in oil and gas pipelines. Since the framework successfully incorporates particle collisions and non-spherical effects, extensions to modeling the multi-phase features of flow in small arteries are foreseeable.

An important task is to combine the particle framework with a fluid flow solver and allow for two-way coupling. As flow solver, we intend to use the fast Lattice Boltzmann code waLBerla from Ulrich Rüde's group in Erlangen. The collaboration is already well established.

Background

Understanding transport of particles in fluids is fundamental in many branches of science, e.g., sedimentation in geology and delivery of nutrients through blood in medicine. Specifically, great interest lies in studying the evolution of a highly dense particle-laden fluid, known as turbidity currents. These flows are involved in the formation of geological structures known as turbidites. As sediments are slowly transported from rivers onto the ocean floor, large amounts of sand and mud can accumulate in submerged regions. If the bed gradient is large enough, sudden events such as tsunamis or earthquakes can trigger an underwater avalanche of the accumulated sediments. This resulting mixture of sand and water is called a turbidity current. While the flow moves along the ocean floor, sediments are constantly deposited and re-suspended, and the dense packing of the suspended particles gives rise to inter-particle collisions. All of these factors makes turbidity currents a highly complicated flow to model. If a region experiences repeated occurrences of turbidity currents, new sedimentary rocks will develop from the settled materials. These deposits are called turbidites, which may often constitute important oil and gas reservoirs.