scholarly journals A theoretical and numerical study of the flow of granular materials down an inclined plane. [Quarterly progress report, January--March 1995]

1995 ◽  
Author(s):  
K.R. Rajagopal
Author(s):  
C. Allery ◽  
S. Gue´rin ◽  
A. Hamdouni ◽  
A. Sakout

We present in this paper an experimental and numerical study about the Coanda effect which causes the sudden reattachment of a jet to an inclined plane. This phenomenon induces a large hysteresis loop, which can be used to reduce the noise produced by an airflow crossing two diaphragms in tandem inside a duct. The angle of the inclined wall with horizontal plane and the flow velocity are the two main parameters studied here. With the aim of doing optimal control, we propose to construct for this flow configuration a low-dimensional dynamical system with a basis issued from a Proper Orthogonal Decomposition.


1994 ◽  
Vol 103 (1-4) ◽  
pp. 63-78 ◽  
Author(s):  
R. Gudhe ◽  
K. R. Rajagopal ◽  
M. Massoudi

2020 ◽  
Vol 117 (15) ◽  
pp. 8366-8373 ◽  
Author(s):  
Sandip Mandal ◽  
Maxime Nicolas ◽  
Olivier Pouliquen

Characterization and prediction of the “flowability” of powders are of paramount importance in many industries. However, our understanding of the flow of powders like cement or flour is sparse compared to the flow of coarse, granular media like sand. The main difficulty arises because of the presence of adhesive forces between the grains, preventing smooth and continuous flows. Several tests are used in industrial contexts to probe and quantify the “flowability” of powders. However, they remain empirical and would benefit from a detailed study of the physics controlling flow dynamics. Here, we attempt to fill the gap by performing intensive discrete numerical simulations of cohesive grains flowing down an inclined plane. We show that, contrary to what is commonly perceived, the cohesive nature of the flow is not entirely controlled by the interparticle adhesion, but that stiffness and inelasticity of the grains also play a significant role. For the same adhesion, stiffer and less dissipative grains yield a less cohesive flow. This observation is rationalized by introducing the concept of a dynamic, “effective” adhesive force, a single parameter, which combines the effects of adhesion, elasticity, and dissipation. Based on this concept, a rheological description of the flow is proposed for the cohesive grains. Our results elucidate the physics controlling the flow of cohesive granular materials, which may help in designing new approaches to characterize the “flowability” of powders.


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