Abstract
In this paper, we present the direct simulation on the Brownian diffusion by the Langevin equation. The model is one dimensional diffusion of Brownian particles suspended in static fluid with absorption walls on both sides. The density of fluid and a particle were assumed to be as same as the one of air and water. At the beginning of the calculation, 3000 particles with 0.1 μm diameter were suspended in 15 cells (Δx=Δy= 2.01μm) randomly. Computational time steps were 10^<-3> and 10^<-4> sec. In this model, the theoretical solution can be derived for the transitional concentration distribution by solving the diffusion equation. It was concluded that the computed concentration distribution is in good agreement with the theoretical solution. In the microscopic point of view, the Brownian diffusion may be computed using the Langevin equation, and the position of a particle can be calculated by this direct numerical simulation.
