Air Bubble Diffusion in Supercritical Open Channel Flow

Abstract

Air bubble entrainment in open channels is called 'white waters'. It is observed in supercritical turbulent flows. The air bubble diffusion process is analysed both analytically and experimentally in uniform equilibrium flows. The solution of the diffusion equation is compared with model and prototype data. The results indicate that the turbulent diffusivity is of the same order of magnitude as the momentum transfer coefficient (i.e. eddy viscosity.). However D_t/v_T is larger on models than on prototype, suggesting that model investigations might not reproduce accurately the air bubble diffusion process