1986 年 29 巻 258 号 p. 4107-4112
Motion of small particles in a viscous flow past many square cylinders spaced regularly is investigated theoretically. In a steady flow past regularly spaced cylinders found by numerically solving the Navier-Stokes equations, trajectories of small particles are numerically found under the assumption that particles are subjected to Stokes' drag force and the viscous flow is not affected by the presence of small particles. As a result, a critical condition that particles always collide with the square cylinders spaced regularly is found as a function of the mass ratio, the Reynolds number and the situation of cylinders. When the particles do not collide with the cylinders, trajectories of particles which are started from arbitrary positions with arbitrary velocities are found to tend to become only one particular trajectory after a sufficiently long time. There theoretical results are confirmed qualitatively by an experiment undertaken in a slow flow of water.