An octree-based immersogeometric approach for modeling inertial migration of particles in channels

• Published in: Computers & fluids Vol. 214; p. 104764
• Main Authors: Xu, Songzhe, Gao, Boshun, Lofquist, Alec, Fernando, Milinda, Hsu, Ming-Chen, Sundar, Hari, Ganapathysubramanian, Baskar
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 15.01.2021; Elsevier BV
• Subjects: Adaptive algorithms; Adaptive mesh refinement; Benchmarks; Channel flow; Finite element method; Grid refinement (mathematics); Immersogeometric analysis; Microchannels; Multiscale analysis; Octree-based mesh; Octrees; Parallel processing; Particle inertial migration; Particle motion; Quadratures; Rigid structures; Rigid-body dynamics; Tracking; Particle inertial migration; Adaptive mesh refinement; Immersogeometric analysis; Octree-based mesh
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2020.104764

In this paper, we develop a scalable, adaptively refined, octree-based finite element approach with immersogeometric analysis to track inertial migration of particles in microchannels. Fluid physics is modeled using a residual-based variational multiscale method, and the particle movement is modeled as rigid body motion. A parallel, hierarchically refined octree mesh is employed as the background mesh, on which a variationally consistent immersogeometric formulation is adopted for tracking the particle motion in the fluid. Adaptations of immersogeometric analysis on an octree background mesh are developed to enable efficient searching of background element for a given surface quadrature point, as well as a distribution of surface quadrature points over processors to reduce memory overhead and better parallelize the surface assembly. An octree-based adaptive mesh refinement algorithm adapted to in-out test in the immersogeometric approach is also developed. The validation of our octree-based immersogeometric approach is carried out using a benchmark case of a sphere settling in quiescent fluid, with good agreement presented. In addition, good strong (and weak) scalability on supercomputing resources for this benchmark case up to 16,384 processes is demonstrated. The proposed method is further deployed for exploring particle migration in straight and converging-diverging channels. This example illustrates the potential of the octree-based immersogeometric approach for efficiently tracking particle motion in complex channel flows – a problem with a diverse array of applications.