An experimental study of the flow field around the flat plate with air injection

In order to investigate the characteristics of the air layer around the bottom of the flat plate when there is air injection,an experiment was conducted for the air-water two-phase boundary layer of the flat plate in a low turbulence water tunnel. The effects of the air flow rate and inflow speed on the macroscopic shape of the air layer were investigated and the change law of the air layer shape was analyzed. The results show that the air layer spreads backward together with the inflow and has a transverse spread angle,which increases as the air flow rate increases and decreases while the inflow speed increases. The flow shape of the air layer is related to the air flow rate and inflow speed. When the non-dimensionalized air flow rate coefficient is less than 0. 610( Cq≤0. 610),the air layer mainly has a bubbly flow; when the non-dimensionalized air flow rate coefficient is greater than 1. 446( Cq ≥1. 446),the air layer has an air-water stratified flow; otherwise,there is a transitional flow that is both bubbly and stratified.