Pulverströme

Pulverströme, translated literally as "powder streams," is a German term referring to the phenomenon of granular materials flowing in a continuous, often cascading manner, similar to liquids. This behavior is observed in a wide range of materials, including sand, grains, salt, and even finer powders like flour or cement. The key characteristic of pulverströme is the transition from a static, granular heap to a dynamic flow when an internal angle of repose is exceeded or when external forces are applied.

The flow of pulverströme is governed by complex interactions between individual particles. While seemingly fluid-like, granular materials exhibit unique properties such as dilatancy (expansion upon shearing) and friction. The rate of flow is influenced by factors like particle size and shape, moisture content, and the geometry of the container or slope. Understanding pulverströme is crucial in various industrial applications, including the design of hoppers, silos, and conveyor systems, as well as in natural phenomena like landslides and avalanches. Research into pulverströme often employs principles from physics, engineering, and materials science to model and predict their behavior.