Transitional granular flows : an experimental approach

"The granular column collapse is a benchmark model to study granular flows over transitional flow regimes using a two-dimensional setup. This research explores the mobility and collapse dynamics of granular columns as a function of the column aspect ratio a = H0/L0, with H0 and L0 as the initial column height and with, respectively. Making use of the simplicity of the experimental setup, several scenarios are evaluated: i) Dry collapse, ii) Submerged collapse, iii) Partially-submerged collapse and, iv) partially-saturated collapse. The results show that the column mobility is controlled by its aspect ratio (a), presenting a clear agreement with previous studies. The final deposit shape is also affected by the initial geometry of the column, marking a transition between trapezoidal deposits for short columns and triangular deposits for tall columns. Additionally, two characteristic times mark the boundaries of the different stages present during the collapse. Focusing on the particle-fluid interaction of the submerged scenario, convective cells are found inside the system, generating a recirculating flow within the column during the collapse. In the partially-submerged scenario, the collapse is observed to generate different types of waves: right-moving waves (seaward) and left-moving waves (landward). The amplitude in seaward waves is found to decrease with the water level, while the landward waves are noticed only in a small range of water levels. Finally, the partially-saturated scenario is evaluated as a final review on the setup capabilities. The presence of water meniscus is observed to decrease the mobility of the column, due to the additional shear strength of the capillary forces."--Tomado del Formato de Documento de Grado.

• Autores: Pinzón Forero, Gustavo Adolfo
• Fecha de publicación: 2019
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/43728
• Acceso en línea: http://hdl.handle.net/1992/43728
• Palabra clave: Materiales granulados - Investigaciones; Materiales granulados - Propiedades mecánicas - Investigaciones; Resistencia de materiales - Investigaciones; Columnas - Investigaciones - Pruebas; Ingeniería
• Rights: openAccess
• License: https://repositorio.uniandes.edu.co/static/pdf/aceptacion_uso_es.pdf