|Front view||Side view|
Our team has tested the efficacy of bubbling on preventing biofouling on panels submerged underwater, resulting in V-shaped clean patterns above the nozzle (top images). To learn what sets the shape of this V region, we are examining the dependence of bubble trajectories (top videos) on nozzle size, flow rate, and angle. This knowledge could inform future designs of bubble rigs, suggesting optimal spacings and required flow rates.
Computationally, I am working on simulations of individual bubbles rising against an inclined wall (bottom videos) to learn how the shear stress on the wall depends on the bubble size, wall angle, and frequency of release. The shear stress can be compared to critical stresses required to remove various types of biofouling.
Simulation (using Basilisk) of a 3 mm-diameter bubble rising in water beneath a wall at an angle of 22.5° from the vertical. Videos are rotated so wall appears vertical. Left movie shows vorticity in the plane z=0, right movie shows the shear stress at the wall in a logarithmic scale between 10-4 Pa (blue) and 1 Pa (red). The threshold of 0.01 Pa suggested by Menesses et al. 2017 is halfway between these bounds, where the color is gray.
Comparison of simulation and experiment at the same conditions, except experiments have a continuous stream of bubbles (flow rate 10 mL/min)