Comparison of flow dynamics and air entrainment under laboratory plunging and spilling breaking waves

Wave breaking plays a vital role in enhancing transfer of mass, momentum, and energy across the air-sea interface. Even though wave breaking has been intensively studied, a vast part of the air entrainment process is still poorly understood. One major reason is that multiphase approaches considering air-water mixture density variation have rarely been used. To quantify certain flow properties that involve air entrainment and fluid density variation, such as the mean and turbulent kinetic energy as well as potential energy under breaking waves, void fraction measurements are essential. In the present study, through combined velocity and void fraction measurements, flow kinematics, turbulence, void fraction, and the effects of void fraction to energy dissipation were investigated. The data uniquely characterize and compare kinematic and dynamic properties of the multiphase flow, including flow structure in the highly aerated region, under plunging and spilling breaking waves.