The free surface begins to deform slightly, but no air is yet trapped.
Air entrainment is not a singular event but a multi-stage process driven by the instability of the air-water interface: Air Bubble Entrainment in Free-Surface Turbulen...
The free surfaces enclose, releasing a single or group of air bubbles into the turbulent flow. Key Drivers and Models The free surface begins to deform slightly, but
A surface cavity develops, reaching deeper into the water while the sides remain smooth. Air Bubble Entrainment in Free-Surface Turbulent Shear Flows
Air Bubble Entrainment in Free-Surface Turbulent Shear Flows
"Air Bubble Entrainment in Free-Surface Turbulent Shear Flows" is a seminal area of study in hydraulic and fluid engineering, primarily defined by the work of Hubert Chanson . This process occurs when turbulence in a liquid becomes strong enough to overcome surface tension and gravity, causing air to be trapped and dispersed as bubbles into the flow. Core Mechanisms of Entrainment