Influence of Gaussian Hill on Concentration of Solid Particles in Suspension Inside Turbulent Boudary Layer

The soil erosion is a major problem that affects the agriculture, climate and health. It is therefore necessary to understand the phenomena that are its wheels in order to either predict or limit it. One of the main problem of this kind of study is the presence of high particle concentration that restricts measurements of either particle concentration or carrier flow rate. In so numerical simulations are essential for detailed studies. Nevertheless these numerical models have to be performant enough and validated with situations that if they are not realistic are representative of phenomena involved. So here we focused on the problem of the possibility of trapping the solid particles in the recirculation zones. We have reproduced in laboratory a configuration representative of sites with enough steep hills to generate recirculation zones during saltation regimes.Measurements have been made of the dispersion of solid particles released from a rectangular area flushed at the ground of a flat plate on which evolved a turbulent boundary layer. The originality here is that it is flushed at the ground and push up the particles to continuously feed the ground at the same mean rate as the mean local erosion rate. One or more Gaussian hills were disposed transversally to the flow downstream the solid particle injection. Various Reynolds number where chosen to caracterise take-off regimes and recirculation regime behind the Gaussian hill(s). One optical system combined with CMOS camera is used successively to measure the velocity of career fluid or solid particles by PIV. Digital Image treatment is used to separate fluid seeding from solid particle images. Supplementary comparison was done to compare velocity field of the career flow for smooth and rough floor only for kinematic around the hill(s).In this paper, in a first part we will present kinematic caracteristics of the flow whereas in a second part of this work, the data will provide some concentration profiles of solid particles. The results presented concerning the velocity and concentration field are related to streamwise vertical planes at the center of the wind tunnel at successive longitudinal positions. For velocity field we will report different regimes for smooth and rough plate. Only one regime will be presented for solid particles. We present in a first part the kinematic study and in the second part results on the concentrations of solid particles.