• Corpus ID: 252438837

Unified Mechanical Erosion Model for Multi-phase Mass Flows

@inproceedings{Pudasaini2022UnifiedME,
  title={Unified Mechanical Erosion Model for Multi-phase Mass Flows},
  author={Shiva P. Pudasaini},
  year={2022}
}

• S. Pudasaini
• Published 22 September 2022
• Materials Science

: Erosion often poses a great challenge in simulating hazardous multi-phase mass flows as it can drastically change the flow behavior, impact force, run-out and deposition morphology by dramatically increas-ing their masses, potentially adversely affecting the population and civil structures. However, there exists no mechanically-explained process-based, unified multi-phase erosion model. Here, we construct a novel, unified, comprehensive and consistent mechanical basal erosion rates for solid and fluid phases and demonstrate their richness, urgency and wide spectrum of applicability. This is achieved by seminally introducing mechanically interacting stress structures across the erosion-interface between the landslide and the bed. All the shear resistances from the bed against the applied shear stresses from the landslide are based on consistent physical principles. The proposed multi-phase interactive shear structures are mechanically superior, dynamically flexible and broader over the existing models. As the total erosion rate is the exact sum of the solid and fluid erosion rates; which are extensive, compact and mechanically fully described; this automatically satisfies the natural criterion. These erosion rates consistently take the solid and fluid fractions from the bed which are customarily supplied to the solid and fluid components in the flow. This overcomes severe limitations inher-ited by existing erosion models, and thus opens ample possibilities for real applications. For the first time, we physically correctly model the essentially composite, intricate erosion velocities of the mobilized particles and fluid from the bed and utilize them to architect erosion-induced net momentum productions that include all the interactions between solids and fluids in the landslide and the bed. With this, we construct complete momentum productions for solid and fluid phases. Both the erosion rates and momentum productions are well constrained. We invent the stress correction factor, erosive-shear-velocity, super-erosion-drift, and the erosion-matrix which inherently characterize complex erosion processes in multi-phase mass flows. This greatly enhances our understanding. By embedding extensive erosion velocities, unified mechanical erosion rates and the advanced net momentum productions into the mass and momentum balance equations, we develop a novel, realistic and mechanically-explained, comprehensive multi-phase model for erosive mass flows. Thus, our approach makes a complete description of multi-phase erosive landslide dynamics by considering all essential aspects associated with erosion including the correct handling of inertia. As the new model covers a broad spectrum of natural processes, it offers great opportunities for practitioners in appropriately solving technical, engineering and geomorphological problems related to complex erosive multi-phase mass flows. ) To physically correctly establish the jumps in shear stresses and momentum fluxes across the erosion-interface between the landslide and the bed substrate, and construct unified, comprehensive and consistent mechanical erosion rates for the solid and fluid phases. We propose multi-phase mechanically-described interactive shear structures containing all the interactions between different phases on either side of the erosion-interface between the flowing landslide and the erodible bed substrate. The sum of the solid and fluid erosion rates will be the total basal erosion rate. The new erosion rate models are broad, well defined and well constrained. ( ii ) To construct extensive and complete erosion-induced net momentum productions for both the solid and fluid phases. This is based on the physically correctly described novel complex erosion velocities of the mobilized particles and fluid from the basal substrate and the unified erosion rates. ( iii ) To develop a realistic and comprehensive multi-phase mechanical erosion model that includes the novel, unified mechanical erosion rates, extended erosion velocities and the advanced net momentum productions into the mass and momentum balance equations. The new approach makes a complete description of the multi-phase erosive landslide by considering all the aspects associated with the erosion-induced momentum productions and the correct handling of the inertia while incorporating the net momentum productions. Moreover, the newly developed stress correction factor, erosive-shear-velocity, super-erosion-drift, and the erosion-matrix further highlight the importance of our modelling approach for the complex erosive multi-phase mass flows.