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| Author(s): |
Jimmy Gabriel Alvarez Zambrano
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica |
| Defense date: | 2023-11-23 |
| Examining board members: |
Erick de Moraes Franklin;
Arthur Vieira da Silva Oliveira;
Fábio Toshio Kanizawa
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| Advisor: | Erick de Moraes Franklin |
| Abstract | |
In ambiental and industrial applications, the transport of solid particles sheared by a turbulent flow is common. In nature, the consequence of complex physical interactions between the air-flow and a sand bed in deserts is the appearance of dunes. The simplest sand formation shaped like a dune is the Barchan dune. Barchans are dunes of crescent form, with a limited supply of sediments under the influence of unidirectional flow. They can appear in a variety of environments, from river beds to Earth’s deserts and the surface of other planets, which motivates efforts to study and understand the physics behind the processes of migration, collisions, and interactions between barchans. Such interactions in barchan dune fields involve a highly dynamic coupling between the fluid flow, the morphology of the bed, and the sediment transport. The time and length scales are an obstacle to observing the morphological evolution of barchan fields directly in eolian environments, therefore an alternative is to study the short-distance binary interaction between barchans in subaquatic environments. In this study, we investigate the perturbations and modifications in the structure of the turbulent flow in the disposition of two barchans with the initial condition of transversal displacement and with longitudinal distance close to collision. Two techniques were used with different data acquisition rates. To acquire data with a lower frequency, two-dimensional Particle Image Velocimetry (2D-PIV) was used, and Particle Tracking Velocimetry (PTV) was used to collect data at a higher frequency. The experiments were conducted in a transparent rectangular channel filled with water, in which a controlled turbulent flow acts on the grains to form the barchans. To compare two conditions, the measurements of the flow were taken with (i) a single dune and (ii) a pair of dunes close to each other with a lateral displacement. We analyzed the interaction fluid flow-barchan observing the velocity fields measured over time and the average profiles of the velocity components and the turbulent stresses (AU) | |
| FAPESP's process: | 20/15624-3 - Turbulent flow over bedforms: experiments |
| Grantee: | Jimmy Gabriel Alvarez Zambrano |
| Support Opportunities: | Scholarships in Brazil - Master |