FM6S_11763:Tue:1440:306
XXI International Congress of Theoretical and Applied Mechanics
Warsaw, Poland, August 15-21, 2004

Fast Numerical Method for the Boltzmann Equation on Nonumiform Grids

Alexei Heintz (1)Piotr Kowalczyk (2)
1. Dept. of Math., Chalmers Univ. of Technology and Gothenburg, Sweden
2. Dept. of Math., Informatics and Mechanics, Warsaw University, Poland


A new numerical method for the solution of the homogeneous Boltzmann equation on nonuniform grids is developed. The collision operator is written using the Fourier transform. This formulation and a special new discretization of the gain part allow for the fast numerical computations on nonuniform grids in velocity space. The computational cost of the algorithm is $O(N_v)+O(\sigma N^6 \log N)$ for a general model of interaction. Here $N_v$ is the number of velocity points, $N$ denotes the number of modes in the Fourier domain and $\sigma<1$ is a small constant depending on the discretization. The results of some numerical test are presented.



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