水面に漂流するマイクロプラスチックの気泡プルームによる回収

抄録

Motion of plastic particles floating on water surface driven by a point-sourced bubble plume is investigated experimentally. According to PIV measurements of water surface flow and PTV applied for plastic particles, we found that particles moved significantly slower than the water surface. The ratio of the particle velocity to the surface flow dips at 50 % in the maximum case. This was attributed to gravity waves propagating on the water surface, of which origin is generated by periodic upheaval of water surface above the bubble plume. We also measured the floating particle motion in a larger water reservoir and found two regimes of the particle motion in the radial direction: the near field having two-dimensional diverging flow and the far field with logarithmic decay of the velocity due to combination of momentum dissipation of the surface flow subject to the gravity waves.