A resolved CFD-DEM method based on the IBM for sedimentation of dense fluid-particle flows

• Published in: Computers & fluids 2021-08, Vol.226, p.104968, Article 104968
• Main Authors: Di, Yingtang, Zhao, Lanhao, Mao, Jia
• Format: Article
• Language: English
• Subjects: Boundary conditions; Circular particle; Computational fluid dynamics; Discrete element method; Immersed boundary method; Iterative methods; Lagrangian equilibrium points; Particle interactions; Sedimentation
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2021.104968

•A resolved coupling approach of fluid dynamics and discrete element method is proposed.•The moving boundaries between fluid and solids are tracked by immersed boundary method.•Detailed resolution of fluid phase and strong coupling effect are achieved.•Dominance of wake interactions for dense particulate flow is reflected accurately. Motivated by the interest in accurate simulation of dense fluid-particle flows, a resolved CFD-DEM method is developed by incorporating computational fluid dynamics and discrete element method (CFD-DEM) with the immersed boundary method (IBM). In this approach, the fluid phase is simulated by the CFD while the individual particles are analyzed by means of the DEM. The direct-forcing IBM, which satisfies the no-slip boundary condition and the divergence-free condition simultaneously, is introduced to handle the interactions between rigid boundaries and fluid with inherent ease of tracking drastically moving geometries by a set of Lagrangian points. The strongly coupled system is then achieved through the successive iterative procedure. A significant advantage of the proposed method is that the fluid phase is fully resolved around the particle phase and as a result, for dense particulate flows where the interaction effects on either phase is considerably strong, the essential influence of the wake flow on particles could be reflected truthfully. The gravity-induced sedimentations of particles are performed to demonstrate the accuracy of the presented resolved method, and the comparison with the results obtained by the conventional unresolved CFD-DEM method is also performed which reveals that the proposed method shows a superiority of the precise description of the fluid-particle interactions over the conventional method especially when the dense particulate flows are involved.