Sand spillage from an open–topped rectangular container when in axial collision

A rectangular box, with an open top and containing sand to a given uniform depth, was swung, pendulum– like, from different heights and made to stop suddenly when it reached the vertical position by impinging against a non–rebounding stop. The length and height of the box, as well as the depth of sand in it, were varied in the different experiments. The volume of sand spilled was measured and related to the speed of impact of the box and other parameters. Observations highly relevant to the fundamental mechanics of the flow of grained materials (e.g. showing the sand surface and the internal movement of the sand after impact) are presented. Formulae correlating many of the measurements are given, which should be of help and significance in assessing the degree of spillage that occurs on impact of a truck.