This is a past event
Professor Benjamin Kneller, Chair in Geology & Petroleum Geology at the University of Aberdeen, will be in Brazil from 14 to 20 October to visit several universities.
He will be in Rio Grande do Sul from 14 to 18/10 visiting the Federal University of Rio Grande do Sul (UFRGS) in Porto Alegre and the University of the Vale do Rio dos Sinos (Unisinos) in São Leopoldo.
On 19/10 Prof Kneller will visit the University of São Paulo (USP), where he will present the seminar "Sediment transport by buoyancy-driven flows in the ocean" at the Institute of Geosciences. Details below.
He will be at the State University of Campinas (UNICAMP) on the 20th.
Professor Kneller will be happy to meet students and researchers, time permitting. Please contact him by email if you want to discuss a suitable time.
Seminar: Sediment transport by buoyancy-driven flows in the ocean
Two principal types of buoyancy-driven flows exist in the ocean; river plumes and turbidity currents. In (positively buoyant) river plumes, the shear layer at the boundary with ambient sea-water (the lower boundary) is typically stable, indicating that the effect of the density gradient dominates over the effect of the fluid shear (gradient Richardson numbers of >0.25). This means that the turbulence that is responsible for sediment suspension is generated by other means. By contrast, the classic view of (negatively buoyant) turbidity currents is that the shear layer at the boundary with ambient sea-water (the upper boundary) is unstable, with gradient Richardson numbers of <0.25. This leads to the formation of Kelvin-Helmholtz instabilities and the generation of much of the turbulence that is responsible for the suspension of sediment, but also for the entrainment of ambient fluid. Additionally, the viscous dissipation of this turbulence is responsible for much of the drag experienced by the current. This view is inconsistent with the persistence of such currents over hundreds to thousands of kilometers over the low gradients of the ocean floor. An alternate view is presented for turbidity currents on low gradients.
Time: 2.30-3.30pmInstituto de Geociências (Institute of Geosciences)Rua do Lago, 562Cidade Universitária - SPAuditório 5 - 1º andar
- Speaker
- Professor Benjamin Kneller
- Contact
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Professor Benjamin Kneller - b.kneller@abdn.ac.uk