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The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
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Phase-field-based multiple-relaxation-time lattice Boltzmann model for incompressible multiphase flows.
1State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 30, 2014
Summary
A new multiple-relaxation-time lattice Boltzmann (LB) model enhances multiphase flow simulations. This phase-field LB model improves interface accuracy and stability, reducing spurious velocities for better fluid dynamics analysis.
Area of Science:
- Computational fluid dynamics
- Fluid mechanics
- Numerical analysis
Background:
- Accurate simulation of incompressible multiphase flows is crucial in many engineering applications.
- Existing phase-field-based lattice Boltzmann (LB) models face challenges with stability and interface accuracy.
- Spurious velocities and kinetic energy fluctuations can limit the reliability of single-relaxation-time LB models.
Purpose of the Study:
- To propose a novel phase-field-based multiple-relaxation-time lattice Boltzmann (LB) model for incompressible multiphase flow.
- To enhance the accuracy and stability of interface capturing in LB simulations.
- To reduce spurious velocities and kinetic energy fluctuations compared to existing models.
Main Methods:
- Developed a LB model using two distribution functions: one for the Cahn-Hilliard equation and another for the Navier-Stokes equations.
- Incorporated a source term in the interfacial evolution equation for exact Cahn-Hilliard derivation.
- Designed a pressure distribution to recover correct hydrodynamic equations, enabling explicit calculation of pressure and velocity fields.
- Validated the model through numerical tests: Zalesak's disk rotation, single vortex, deformation field, and static droplet.
Main Results:
- The proposed model demonstrates superior stability and improved interface capturing accuracy compared to previous phase-field LB models.
- Effectively reduces spurious velocity and kinetic energy fluctuations when compared to single-relaxation-time LB models.
- Successfully applied to investigate Rayleigh-Taylor instability at high Reynolds numbers.
Conclusions:
- The developed phase-field-based multiple-relaxation-time LB model offers a robust and accurate approach for simulating incompressible multiphase flows.
- The model provides significant improvements in stability and interface accuracy, making it suitable for complex fluid dynamics problems.
- This work contributes to advancing LB methods for multiphase flow simulations, particularly for phenomena like Rayleigh-Taylor instability.
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