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Force methods for the two-relaxation-times lattice Boltzmann
1University of Groningen, Nijenborgh 9, 9747 AG Groningen, The Netherlands.
Physical Review. E
|January 20, 2021
Summary
The two-relaxation-times collision in lattice Boltzmann methods improves accuracy by reducing viscosity-dependent errors. This study shows how to integrate force methods, proving that those with a first-order velocity moment maintain accuracy.
Area of Science:
- Computational fluid dynamics
- Numerical methods
Background:
- The steady lattice Boltzmann method (LBM) is crucial for fluid simulations.
- The two-relaxation-times (TRT) collision operator enhances LBM by minimizing viscosity-dependent numerical errors.
Purpose of the Study:
- To integrate popular force methods into the TRT collision for LBM.
- To analyze the impact of force methods on the viscosity independence of TRT-LBM.
Main Methods:
- Rewriting force methods into a generic equation to identify commonalities and differences.
- Theoretical analysis of force methods based on velocity moments.
- Numerical validation of the theoretical findings.
Main Results:
- Force methods incorporating a second-order velocity moment of the force disrupt the viscosity independence of TRT-LBM.
- Force methods utilizing only a first-order velocity moment of the force preserve viscosity independence.
- Demonstration of the theoretical proof through numerical simulations.
Conclusions:
- The choice of force method significantly impacts the numerical accuracy of TRT-LBM.
- First-order velocity moment force methods are recommended for maintaining viscosity independence in TRT-LBM simulations.
- This work provides a framework for understanding and selecting appropriate force methods for LBM.
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