> C. Ruyer-Quil
Internal dynamics of a free surface viscoplastic flow down an inclined plane
Perrine Freydier (IRSTEA)
Natural muddy debris flows can be modeled as non-Newtonian viscoplastic fluids. These flows are generally represented using models based on the integral approach (Shallow Water) that consist of taking the depth average of the local conservation equations. These models take into account terms depending on the shape of the velocity profile.
The aim of our experimental set up is to improve our knowledge about the shape of velocity profiles and the position of the interface between sheared and unsheared region (plug), especially in the vicinity of the front. Experiments are conducted in a 3-m-long and 0.2 m wide inclined channel whose bottom is constituted by an upward-moving conveyor belt. Carbopol microgel is used as a homogeneous transparent viscoplastic material. We use PIV technique (Particle Image Velocimetry) to obtain velocity field over the longitudinal direction both in the uniform zone and within the head where flow thickness is variable and where recirculation take place.