Fully resolved simulations of viscoelastic suspensions by an efficient immersed boundary-lattice Boltzmann method--颗粒学报PARTICUOLOGY

Qin, S., Jiang, M., Ma, K., Su, J., & Liu, Z. (2023). Fully resolved simulations of viscoelastic suspensions by an efficient immersed boundary-lattice Boltzmann method. Particuology, 75, 26-49. https://doi.org/10.1016/j.partic.2022.06.004

Fully resolved simulations of viscoelastic suspensions by an efficient immersed boundary-lattice Boltzmann method

Shenxu Qin ^a, Maoqiang Jiang ^a *, Kuang Ma ^a, Jin Su ^b, Zhaohui Liu ^a

a State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
b School of Science, Xi'an Polytechnic University, Xi'an, 710048, China

10.1016/j.partic.2022.06.004

Volume 75, April 2023, Pages 26-49

Received 10 April 2022, Revised 25 May 2022, Accepted 7 June 2022, Available online 24 June 2022, Version of Record 12 July 2022.

E-mail: jiangmq@hust.edu.cn

Highlights

• A simple and efficient BTDF-IBM-LBM method for viscoelastic suspensions was developed.

• Diffusivity constant and asynchronous calculation were studied for accuracy and efficiency.

• Comprehensive validations were exhibited through several benchmark flows.

• Stabilization and destabilization effect of elasticity on suspension behavior were revealed.

Abstract

An efficient immersed boundary-lattice Boltzmann method (IB-LBM) is proposed for fully resolved simulations of suspended solid particles in viscoelastic flows. Stress LBM based on Giesekus and Oldroyd-B constitutive equation are used to model the viscoelastic stress tensor. A boundary thickening-based direct forcing IB method is adopted to solve the particle–fluid interactions with high accuracy for non-slip boundary conditions. A universal law is proposed to determine the diffusivity constant in a viscoelastic LBM model to balance the numerical accuracy and stability over a wide range of computational parameters. An asynchronous calculation strategy is adopted to further improve the computing efficiency. The method was firstly applicated to the simulation of sedimentation of a single particle and a pair of particles after good validations in cases of the flow past a fixed cylinder and particle migration in a Couette flow against FEM and FVM methods. The determination of the asynchronous calculation strategy and the effect of viscoelastic stress distribution on the settling behaviors of one and two particles are revealed. Subsequently, 504 particles settling in a closed cavity was simulated and the phenomenon that the viscoelastic stress stabilizing the Rayleigh–Taylor instabilities was observed. At last, simulations of a dense flow involving 11001 particles, the largest number of particles to date, were performed to investigate the instability behavior induced by elastic effect under hydrodynamic interactions in a viscoelastic fluid. The elasticity-induced ordering of the particle structures and fluid bubble structures in this dense flow is revealed for the first time. These simulations demonstrate the capability and prospects of the present method for aid in understanding the complex behaviors of viscoelastic particle suspensions.

Graphical abstract

Keywords

Fully resolved simulation; Lattice Boltzmann method; Immersed boundary method; Viscoelastic suspension; Particle sedimentation

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