Turbulence generated by a vertical grid in open channel flow is experimentally investigated. A hot-film anemometer and an ultra-sonic current meter are used to measure the turbulence.
　In case of the flow without a grid, the mean velocity profile is in good accordance with logarithmic law, and the distribution of relative intensity of turbulence increases with the distance from the surface. A grid installed in the flow, however, makes these distributions uniform over the whole depth, and decreases the energy distribution at lower frequency but increases at higher frequency.
　Lateral diffusion coefficients are estimated to be in the range from 0.3 cm2/s to 0.6 cm2/s in case of the flow without a grid, while vertical diffusion coefficients are one tenth of lateral diffusion.
　The measurements of turbulence by ultra-sonic current meter yield a slight under-estimation, which comes from the averaging process of the velocity between two oscillators, and overestimation, which comes from the additional effect of the wake by oscillators. The averaging effect acts remarkably in intense turbulent field, while the wake behind the oscillators reveals its influence in weak turbulent field.