2023 Volume 79 Issue 17 Article ID: 23-17006
Air density distribution above the bubbling water surface was visually measured using the Background Oriented Schlieren (BOS) method. It was confirmed that the BOS method is applicable to a density measurement of the air surrounding a water droplet that is slowly evaporating in a still air. The BOS method sucsessfully visualized the high-density air released from a bursting bubble is transported upward through diffusion. The air just above the bubbling surface, therefore, tends to have a higher average density than the bulk air, which generates the negative vertical gradient of air pressure. The pressure gradient near the bubbling surface is one of the important factor to determine the initial conditions of the sea spray droplets; further study about the air density and pressure field above the bubbling surface would be needed for its quantification.
