Experimental investigation of oxygen transfer efficiency in hydraulic jumps, plunging jets, and plunging breaking waves

The scope of the paper is to analyse the different similarities of air entrainment among the hydraulic jumps, plunging jets, and plunging breaking waves and to discuss current practices. The measured data are reexamined and scrutinised to investigate the gas exchange phenomena through an air-water interface. In particular, oxygen transfer efficiency and penetration depth by air bubbles are discussed. The calculated results highlight that the oxygen transfer efficiency is decreased with the increase of energy dissipation rate both in plunging jets and breaking waves. In contrast, it is shifted almost parallel in the case of hydraulic jumps. In addition, the aeration lengths in the hydraulic jumps and penetration depths both in plunging jets and plunging breaking waves were dependent on the jet impact velocity. HIGHLIGHTS Air bubble entrainments through hydraulic jumps, plunging jets, and plunging breaking waves are studied.; Aeration lengths in the hydraulic jump and penetration depths in the plunging jets and plunging breaking waves were determined.; Dissolved oxygen, as well as oxygen transfer efficiency, were measured and compared among the phenomena.; Scale effects were observed among the phenomena in terms of the oxygenation.;