Stationary and oscillatory flows through porous media: effects of the specific surface
Ecoulements stationnaires et oscillants à travers des milieux poreux : effets de la surface spécifique
Résumé
The purpose of this work was to study the effects of the specific surface on the energy dissipation through a "model" porous medium constituted by a network of emerging vertical cylinders. Experiments have been performed in a ten metres long hydraulic open-channel. Three porous media were used with various cylinder diameters. The porous structure models consisted in regular networks of cylinders of constant diameter. The effect of specific surface have been analysed by using three different cylinder diameters while keeping constant the porosity. Two series of experiments are presented. On one hand, measurements in stationary flow conditions, with various velocities and depths, demonstrated the significant influence of specific surface on pressure drop through the porous media. On the other hand, a second series of experiments has focused on the propagation of regular waves through the porous structures. The role played by the specific surface both on wave attenuation and interference processes was shown to be significant. The greater is the specific surface, the stronger is the damping.