Experimental Study on Hydrodynamics Characters of Flow Laden with Micro-bubbles
The effect of micro-bubbles on the hydrodynamics characters in the turbulent boundary layer is quite complex. In order to clarify the influence of micro-bubbles on coherent structure, turbulence channel flows laden with and without micro-bubbles were experimentally studied by using particle image velocimetry (PIV) technique at a Reynolds number of Re = 8.9×10 4 . Micro-bubbles were produced by the electrolysis of water in a low speed circulating water tunnel. Proper orthogonal decomposition (POD) method was used to analyze the coherent structures of the flow fields. The results show that the micro-bubble decreases the large scale structure and suppresses the intensity of wall-normal vorticity in the near wall region. The longitudinal speed streaks numbers decrease and the energy cumulative growth rate becomes moderate due to the micro-bubbles injection.