Schwarzmeier C, Rüde U (2021)
Publication Type: Conference contribution, Conference Contribution
Publication year: 2021
Event location: Virtual Conference
We present an analysis and a numerical comparison of different boundary conditions for the free
surface lattice Boltzmann method (FSLBM). The FSLBM is a volume-of-fluid-based approach for
simulating multiphase flow in which the dynamic of the lighter and less viscous phase, i.e., the gas
phase, is neglected. Therefore, the problem essentially reduces to a free surface problem where fluid
flow is only simulated in the liquid phase. The computational domain is split into gas and liquid
cells which are separated by a closed layer of interface cells. As flow is not simulated in gas cells,
particle distribution functions (PDFs) are only available in liquid and interface cells. Thus, the
PDFs streaming from gas to liquid are unknown and need to be reconstructed with respect to a free
surface boundary condition. In the original approach [1], not only missing PDFs are reconstructed
but also PDFs that are already known. This, however, discards available and valid information
such that one might consequentially consider reconstructing only those PDFs that are actually
missing. Some authors have mentioned that the latter approach avoids anisotropic artifacts [2],
while others have not found any significant difference in their simulation results when comparing
the two approaches [3].
We theoretically analyze and compare these two approaches and validate them with different
numerical simulation setups.
[1] C. Körner, M. Thies, T. Hofmann, N. Thürey, and U. Rüde, “Lattice Boltzmann Model for
Free Surface Flow for Modeling Foaming,” Journal of Statistical Physics, vol. 121, no. 1, 2005.
doi: 10.1007/s10955-005-8879-8.
[2] S. Bogner, R. Ammer, and U. Rüde, “Boundary conditions for free interfaces with the lattice
Boltzmann method,” Journal of Computational Physics, vol. 297, 2015. doi: 10.1016/j.jcp.
2015.04.055.
[3] Y. Thorimbert, B. Chopard, and J. Lätt, “Implementation of lattice Boltzmann free-surface
and shallow water models and their two-way coupling,” MethodsX, vol. 8, 2021. doi: 10.1016/
j.mex.2021.101338.
APA:
Schwarzmeier, C., & Rüde, U. (2021). Analysis and comparison of free surface lattice Boltzmann boundary conditions. In Proceedings of the 30th International Conference on Discrete Simulation of Fluid Dynamics. Virtual Conference.
MLA:
Schwarzmeier, Christoph, and Ulrich Rüde. "Analysis and comparison of free surface lattice Boltzmann boundary conditions." Proceedings of the 30th International Conference on Discrete Simulation of Fluid Dynamics, Virtual Conference 2021.
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