Orateur
Description
Fiber reinforcement of granular materials is a cost-effective strategy widely used in applications ranging from coastal erosion protection to eco-construction materials and fiber-reinforced concretes. The efficiency of such reinforcement strongly depends on the mixing process and on the resulting spatial distribution and orientation of fibers within the granular matrix. To better identify the parameters controlling fiber distribution and orientation, we investigate experimentally the dynamics of a single fiber immersed in a dense granular flow. We systematically explore the influence of both flow conditions and fiber properties on fiber transport and orientation. We show that the center-of-mass dynamics of the fiber can be described by an effective diffusion process characterized by a diffusion coefficient that depends on the fiber length relative to the grain size. In addition, we analyze the angular dynamics of the fiber and demonstrate that fibers preferentially align with the flow direction, with longer fibers exhibiting stronger alignment. These fundamental results constitute a first step toward rationalizing the mixing processes in grain–fiber mixtures.