Granular flow fusion From local particle interactions to collective flow behaviour

This thesis investigates the flow behaviours of granular materials, which are critical in numerous industrial, geological, and biological settings. Granular materials exhibit complex mechanical behaviour due to the interplay between microscopic interactions and collective flow dynamics. This research aims to bridge the gap between these scales, providing a comprehensive understanding of granular flow by leveraging advanced imaging techniques and flow testers.
The study highlights the need to link microscopic properties, such as particle interactions, to macroscopic flow behaviour. This is achieved by developing new methodologies and tools, including an X-ray compatible rheometer and advanced Magnetic Resonance Imaging (MRI) techniques. These innovations allow for simultaneous measurement and imaging of granular flows, enabling a deeper exploration of flow characteristics under various conditions. A significant focus is placed on understanding how factors such as particle softness, friction, and adhesion influence shear behaviour and flow dynamics. The research uncovers the role of pressure sensitivity and adhesion in determining flow behaviour, particularly in complex systems like suspensions and cohesive granular materials. By examining these systems, the thesis provides new insights into how micro-level interactions govern macroscopic flow, offering a comprehensive understanding of granular rheology. Overall, this thesis contributes to the field by advancing techniques to study granular materials and by offering new perspectives on the fundamental mechanics driving their flow behaviours. The findings have broad implications, enhancing the predictive capabilities for granular flow in various applications.