In this paper the behaviors of settling particles in turbulent shear flow are investigated and the statistical properties of distribution of the particles at the bottom are obtained experimentally and theoretically. For the properties of distribution of the particles, the mean settling length of the particle, that is, the mean value of the streamwisely transporte length of the particle, and the standard deviation of the settling length are considered. These statistical properties are obtained by experiment and the trajectories of the settling particles are photographed by storoboscopic light. Then, on the basis of these experimental results, the stochastic models for the behaviors of the settling particles are developed. These models can explain well the actual phenomena, and it is found that these stochastic models are to be pertinent. Problems to be solved in the future are discussed
