Abstract:
This paper studies the effects of an air bubble curtain on surface water waves. Water
particle velocities and free surface elevations were measured simultaneously at two cross-shore
sections downstream the air bubble curtain. Measurements were carried out for regular waves
regarding different air bubble curtain configurations. Free surface elevations were measured using
resistive gauges and the instantaneous velocities were acquired using an Acoustic Doppler
Velocimeter (ADV). The characteristics of the free surface elevation, velocity field and turbulence
are analyzed and discussed. The free surface elevation was found to be constantly attenuated by the
air bubble curtain. The phase-averaged velocity profiles also depict the effect of the air bubbles in the
flow field by generating milder longitudinal velocities (u) and by increasing the transverse component
of the velocity (w). The increase in the turbulence intensity and the different energy spectrum
produced by the air bubble curtain is also analyzed. The experimental results indicate that the
thickness of the air bubble curtain and the total air flow rate affects the wave field.
