Influence of a Bubble Curtain Device on Microplastics Dynamics

Air bubble curtains have been applied to a wide range of situations, from the attenuation of underwater noise, debris control, and containment of suspended sediment to the reduction in saltwater intrusion. This work conducts a preliminary numerical study on the influence of a bubble curtain device on microplastic dynamics. Simulations are conducted with a two-phase unsteady model, and the trajectories of the microplastic particles are computed with the Discrete Phase Model (DPM). Particles are injected upstream of the bubble curtain, and their transport is analyzed under different flow conditions. Results show that the ratio between the water velocity and the air injection velocity can significantly impact the efficiency of the device in directing the particles toward the surface. Furthermore, a higher degree of turbulent mixing is seen for lower water velocities. This study highlights the intricate flow behavior, and the need for a deeper understanding of other variables such as the microplastic size and concentration and the geometry of the air injection system.