Physics – Fluid Dynamics
Scientific paper
2009-08-31
Physics
Fluid Dynamics
28 pages, 15 figures
Scientific paper
In this work, we have theoretically analyzed and numerically evaluated the accuracy of high-order lattice Boltzmann (LB) models for capturing non-equilibrium effects in rarefied gas flows. In the incompressible limit, the LB equation is proved to be equivalent to the linearized Bhatnagar-Gross-Krook (BGK) equation. Therefore, when the same Gauss-Hermite quadrature is used, LB method closely assembles the discrete velocity method (DVM). In addition, the order of Hermite expansion for the equilibrium distribution function is found not to be correlated with the approximation order in terms of the Knudsen number to the BGK equation, which was previously suggested by \cite{2006JFM...550..413S}. Furthermore, we have numerically evaluated the LB models for a standing-shear-wave problem, which is designed specifically for assessing model accuracy by excluding the influence of gas molecule/surface interactions at wall boundaries. The numerical simulation results confirm that the high-order terms in the discrete equilibrium distribution function play a negligible role. Meanwhile, appropriate Gauss-Hermite quadrature has the most significant effect on whether LB models can describe the essential flow physics of rarefied gas accurately. For the same order of the Gauss-Hermite quadrature, the exact abscissae will also modestly influence numerical accuracy. Using the same Gauss-Hermite quadrature, the numerical results of both LB and DVM methods are in excellent agreement for flows across a broad range of the Knudsen numbers, which confirms that the LB simulation is similar to the DVM process. Therefore, LB method can offer flexible models suitable for simulating continuum flows at Navier Stokes level and rarefied gas flows at the linearized Boltzmann equation level.
Meng Jianping
Zhang Yonghao
No associations
LandOfFree
Accuracy analysis of high-order lattice Boltzmann models for rarefied gas flows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Accuracy analysis of high-order lattice Boltzmann models for rarefied gas flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Accuracy analysis of high-order lattice Boltzmann models for rarefied gas flows will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-220601