Postponed - Lunchtime Seminar: LES of Gravity Currents – Roughness Elements, Non-erodible Obstacles and Slopes

  • 02 Apr 2020
  • 12:30 - 13:30
  • Westvest 7, 2611 AX Delft
Western Europe
Video Conference Room

Summary of Research

Gravity currents are mainly generated by density differences within a fluid or between two fluids. They contain a front region usually called the head, a dissipative wake region, in which Kelvin-Helmholtz billows are shed, and a tail. The last two regions form the body of the current. The motion of the fluid behind the head depends on the slope of the bed. Gravity currents occur widely in nature. The presence of density differences of only a few percent can be enough to induce a gravity current that travels over very long distances. Predicting the evolution of turbulent gravity currents is of great interest in many areas of geophysics and engineering, in particular due to their impact on the environment. For example, erosion by gravity currents is one of the main causes of formation of submarine canyons on continental slopes and plays a determinant role in transporting sediments from shallower to deeper regions in water environments. The propagation of a gravity current is often accompanied by disastrous damage.
Large eddy simulations (LES) of these currents aim to develop insight into the flow physics of highly-turbulent Boussinesq gravity currents in lock-exchange configuration propagating over an array of large-scale roughness elements, on slopes, and interaction of constant-flux gravity currents with non-erodible submerged obstacles. Simulation of gravity current propagating over a smooth flat bed serves as a benchmark in the study. The numerical results allow us to analyze the impact of the bed topography on sediment entrainment capacity due to the passage of a compositional gravity current.

About the speaker

Talia Tokyay got her BSc degree in Civil Engineering in 2003 from Middle East Technical University (METU) at Ankara, Turkey. She did her postgraduate study at the University of Iowa, USA and was a graduate research assistant at IIHR-Hydroscience and Engineering, where she worked on various computational fluid dynamics (CFD) related projects, from 2003 until 2010. She received her MSc in 2005 and her PhD in 2010 from the same institution. From May 2010 until August 2012, she worked as a postdoctoral research associate at Ven Te Chow Hydrosystems Laboratory at the University of Illinois at Urbana-Champaign. She took the role of assistant professor at the Department of Civil Engineering in METU between February 2015 and August 2017. Her primary research focuses on CFD, flow-structure interaction, and fundamental and applied research in the areas of hydraulics and water resources. She has over 15 years of experience in RANS and LES simulations of flows relevant to civil and environmental engineering including flow over riffle/pool sequences, flow in/around various structures such as ADCP, rain gauges and traffic signs on highways, flow in pump intakes and draft tubes of hydro turbines, flow around gates, weirs and spillway structures. However, since 2005 she has been infatuated with gravity current research, which she still actively pursues as an independent researcher.

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