arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2102.08559math.NAcs.NAphysics.flu-dyn
收藏

具有自适应碰撞算子的Boltzmann方程数值求解器

Numerical Solver for the Boltzmann Equation With Self-Adaptive Collision Operators

Zhenning Cai, Yanli Wang

摘要:

我们使用Burnett谱方法来求解Boltzmann方程,其碰撞项通过分别处理解的低频部分和高频部分来建模。对于表示分布函数的草图的低频部分,应用二进制碰撞,而对于表示更精细细节的高频部分,应用BGK近似。在每一个时间步长上,在每个网格单元上自适应地选择控制高频部分和低频部分的比率的参数。这种自适应是基于描述模型碰撞项和原始二进制碰撞项之间的差异的误差指示符。该指标是通过控制二次项的建模误差与线性算子。我们的数值实验表明,这样的误差指示器是有效的和计算负担得起的。

英文摘要:

We use the Burnett spectral method to solve the Boltzmann equation whose collision term is modeled by separate treatments for the low-frequency part and high-frequency part of the solution. For the low-frequency part representing the sketch of the distribution function, the binary collision is applied, while for the high-frequency part representing the finer details, the BGK approximation is applied. The parameter controlling the ratio of the high-frequency part and the low-frequency part is selected adaptively on every grid cell at every time step. This self-adaptation is based on an error indicator describing the difference between the model collision term and the original binary collision term. The indicator is derived by controlling the quadratic terms in the modeling error with linear operators. Our numerical experiments show that such an error indicator is effective and computationally affordable.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑