| Full text | |
| Author(s): |
Lima, N. C.
;
Assis, W. R.
;
Borges, D. S.
;
Franklin, E. M.
Total Authors: 4
|
| Document type: | Journal article |
| Source: | JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE; v. 130, n. 6, p. 17-pg., 2025-06-01. |
| Abstract | |
We investigate details of the interaction of subaqueous barchans with dune-size obstacles by carrying out numerical simulations where the fluid is solved at the grain scale and the motions of individual grains are computed at all time steps. With the outputs, we analyze the disturbances of the fluid flow, the trajectories of grains, and the resultant force on each grain, the latter being unfeasible from experiments and field measurements. We show that in some cases particles pass over the obstacle, while in others they completely circumvent it (without touching it), or are even blocked. For the circumvention and blocking cases, which we call bypass and trapped, respectively, we show the existence of a strong vortex between the lee face of the dune and the obstacle. This vortex results from the interactions of recirculation regions and horseshoe vortices, and has enough strength to deviate the main flow and carry grains around the obstacle in those cases. Our results shed light on the reasons for passing over, circumventing, and blocking, and contribute to our understanding of dunes in the presence of large obstacles such as hills, crater rims, and human constructions. (AU) | |
| FAPESP's process: | 19/10239-7 - Bed-load instabilities: granular dynamics and interaction with the fluid flow |
| Grantee: | Willian Righi Assis |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 22/01758-3 - Turbulent flow interacting with dense granular media: perturbations on the flow structure |
| Grantee: | Danilo da Silva Borges |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 18/14981-7 - Modeling of dense granular flows: experiments, numerical simulations and stability analyses |
| Grantee: | Erick de Moraes Franklin |
| Support Opportunities: | Research Grants - Young Investigators Grants - Phase 2 |
| FAPESP's process: | 19/20888-2 - CFD-DEM simulations of fluidized beds |
| Grantee: | Nicolao Cerqueira Lima |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |