Birth of a subaqueous barchan dune

Autor(es)

Alvarez, Carlos A. ; Franklin, Erick M.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW E; v. 96, n. 6, p. 7-pg., 2017-12-18.

Resumo

Barchan dunes are crescentic shape dunes with horns pointing downstream. The present paper reports the formation of subaqueous barchan dunes from initially conical heaps in a rectangular channel. Because the most unique feature of a barchan dune is its horns, we associate the time scale for the appearance of horns to the formation of a barchan dune. A granular heap initially conical was placed on the bottom wall of a closed conduit and it was entrained by a water flow in turbulent regime. After a certain time, horns appear and grow, until an equilibrium length is reached. Our results show the existence of the time scales 0.5t(c) and 2.5t(c) for the appearance and equilibrium of horns, respectively, where t(c) is a characteristic time that scales with the grains diameter, gravity acceleration, densities of the fluid and grains, and shear and threshold velocities. (AU)

• Processo FAPESP: 16/13474-9 - Instabilidades em escoamentos granulares densos
• Beneficiário: Erick de Moraes Franklin
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/19562-6 - Transporte de grãos por leito móvel e instabilidades associadas
• Beneficiário: Erick de Moraes Franklin
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores