Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Effect of unsteady flow dynamics on the impact of monodisperse and bidisperse granular flow
https://orcid.org/0000-0002-9935-7717
Abstract Protective barriers provide crucial resistance against the impact of granular flows. However, the adoption of characterized flow depth and velocity values in impact force estimation remains unclear and requires further investigation, especially with consideration of unsteady flow dynamics. Previous practices suggest that the bulk flow velocity with the assumption of uniform distribution should be used in impact force estimation, while we observe the lower part of the flow consistently exhibits lower velocities than the upper part, because granular shear behavior is enhanced within the boundary layer, which strongly affects the flow velocity. As a result, using a bulk velocity in debris impact force estimation may result in that a larger dynamic pressure coefficient must be used in hydrodynamic model. We made a quantitative assessment. For rapid granular flows, the use of a bulk velocity to calculate the dynamic force component could result in underestimation of approximately 10–30%. Therefore, based on the numerical results, it is suggested that the average velocity of the upper 50% of the flow body can be adopted in impact force estimation. If the front flow depth is used to calculate the dynamic impact force component, the results may be approximately 50% lower than the true value, which indicates that the dynamic force on a barrier is likely not controlled by the granular flow front and that a maximum flow depth may be more appropriate if a hydrodynamic model is adopted. In addition, it seems that the strategy we proposed can be used for both of monodisperse and bidisperse granular flow when boulder impact is excluded.
Effect of unsteady flow dynamics on the impact of monodisperse and bidisperse granular flow
https://orcid.org/0000-0002-9935-7717
Abstract Protective barriers provide crucial resistance against the impact of granular flows. However, the adoption of characterized flow depth and velocity values in impact force estimation remains unclear and requires further investigation, especially with consideration of unsteady flow dynamics. Previous practices suggest that the bulk flow velocity with the assumption of uniform distribution should be used in impact force estimation, while we observe the lower part of the flow consistently exhibits lower velocities than the upper part, because granular shear behavior is enhanced within the boundary layer, which strongly affects the flow velocity. As a result, using a bulk velocity in debris impact force estimation may result in that a larger dynamic pressure coefficient must be used in hydrodynamic model. We made a quantitative assessment. For rapid granular flows, the use of a bulk velocity to calculate the dynamic force component could result in underestimation of approximately 10–30%. Therefore, based on the numerical results, it is suggested that the average velocity of the upper 50% of the flow body can be adopted in impact force estimation. If the front flow depth is used to calculate the dynamic impact force component, the results may be approximately 50% lower than the true value, which indicates that the dynamic force on a barrier is likely not controlled by the granular flow front and that a maximum flow depth may be more appropriate if a hydrodynamic model is adopted. In addition, it seems that the strategy we proposed can be used for both of monodisperse and bidisperse granular flow when boulder impact is excluded.
Effect of unsteady flow dynamics on the impact of monodisperse and bidisperse granular flow
https://orcid.org/0000-0002-9935-7717
Abstract Protective barriers provide crucial resistance against the impact of granular flows. However, the adoption of characterized flow depth and velocity values in impact force estimation remains unclear and requires further investigation, especially with consideration of unsteady flow dynamics. Previous practices suggest that the bulk flow velocity with the assumption of uniform distribution should be used in impact force estimation, while we observe the lower part of the flow consistently exhibits lower velocities than the upper part, because granular shear behavior is enhanced within the boundary layer, which strongly affects the flow velocity. As a result, using a bulk velocity in debris impact force estimation may result in that a larger dynamic pressure coefficient must be used in hydrodynamic model. We made a quantitative assessment. For rapid granular flows, the use of a bulk velocity to calculate the dynamic force component could result in underestimation of approximately 10–30%. Therefore, based on the numerical results, it is suggested that the average velocity of the upper 50% of the flow body can be adopted in impact force estimation. If the front flow depth is used to calculate the dynamic impact force component, the results may be approximately 50% lower than the true value, which indicates that the dynamic force on a barrier is likely not controlled by the granular flow front and that a maximum flow depth may be more appropriate if a hydrodynamic model is adopted. In addition, it seems that the strategy we proposed can be used for both of monodisperse and bidisperse granular flow when boulder impact is excluded.
Effect of unsteady flow dynamics on the impact of monodisperse and bidisperse granular flow
Zhang, Bei (Autor:in) / Huang, Yu (Autor:in)
2022
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
BKL:
56.00$jBauwesen: Allgemeines
/
38.58
Geomechanik
/
38.58$jGeomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
56.00
Bauwesen: Allgemeines
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB18
| British Library Online Contents | 2017
| British Library Online Contents | 2017
| Springer Verlag | 2022
| Springer Verlag | 2008