| Mon April 27th 2009 14:00 HR Z203 | Seminar | Role of air in a loose bed of sand Pieter Palsma |
Details:This research focussed at two parts. The first was impacting objects on a loose bed of sand. The dynamics of a quasi 2D and a 3D setup are comparable and follow the force model proposed by Durian et al. The height of the closure scales with the final depth, but if there are two closures, the lower closure is more influenced by the final depth. The second part focussed at flow through a loose bed of sand. It has been proven that to overcome the excess pressure difference a flow of air is generated, and the mechanism is not driven by diffusion. The permeability (porosity) of a loose bed of sand is 4.5 ± 0.5·10−12 m2 and remains constant for great enough bed heights. The packing fraction is constant at 0.39 ± 0.01, this also only holds at great enough bed heights. Great enough means that the bed height is greater then the sides of thecontainer. | ||
