Using a small two-layer flow channel W15×D30×L310cm, experiments have been conducted of the salt water current which flows turbulently under a pool of fresh water. Hot-film anemometers were used for the measurements of mean velocity profiles and turbulent velocities, and electric conductivity meters for density profiles. Experiments were made initially for 5 cm width and then for 15 cm, varying the intensity of turbulence of lower flows.
　It was found from the experimental results that the entrainment coefficient E is not a function of only a overall Richardson number Ri*; the stronger the turbulence, the larger E is. At the usual experimental conditions in the case of 15 cm width the entrainment coefficient E was found to be E=1.0×10-3Ri*-1. A characteristic length of the density profile lp, is closely related with the generation of interfacial waves and it is represented as a function of Ri* for the same turbulence intensity.
　Some light was shed on the turbulence structure of the lower layer flows. Furthermore it was found that the log-law is valid to the velocity profiles near the interface just as the law of the interface proposed by Csanady (1978).