Application of imaging techniques in dam-break flow experiments with crushed walnut shells

This paper reports applications of imaging techniques in the study of granular flows. Walnut shells are commonly used as artificial sediment in granular flow or sediment transport experiments. Being a porous material, density, shape and representative diameter of the walnut shell grains change when they are saturated in water. The first part of the paper presents the use of image analysis techniques to determine particle diameter and shape of dry and saturated crushed walnut shells. The differences are related to the quantity of water absorbed. Having determined the properties of walnut shells under dry and saturated conditions, the second part of the paper discusses video imaging techniques that can be used to extract the whole field velocity distribution in dam-break flows of crushed walnut shells under dry and submerged conditions. The paper discusses methodology and presents some preliminary data and conclusions.