Unravelling the effects of turbulence: Vanishing tip vortices, scattering waves, and enhanced gas transfer

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• R. Jason Hearst; Professor, Norwegian University of Science & Technology (NTNU), Trondheim, Norway
• Wednesday 16 October 2024, 14:00-15:00
• Board Room.

If you have a question about this talk, please contact Anna Walczyk.

We will explore three topics where recent advances in experimental turbulence measurements have enabled new discoveries. First, time-resolved volumetric measurements of the wake of a model wind turbine are used to investigate the often-observed phenomenon whereby vortices vanish rapidly downstream of a wind turbine. Shifting to air-water interfacial flows, we explore the mutual interaction of surface waves and subsurface turbulence with specific focus on enstrophy enhancement and wave scattering. Finally, it will be demonstrated that turbulence enhances the rate at which environmentally significant gases, e.g. O2, CO2 , transfer from air to water by up to 45%. This will be accompanied by a brief demonstration of recent advances in the measurement of these flows including quantifiable laser-induced fluorescence of O2 concentration in water while simultaneously measuring the velocity field and surface topology, as well as an introduction to a new co-flowing air-water facility with independently controllable turbulence in each phase using active turbulence grids.

Bio: Jason Hearst is a Professor at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. His primary research activities are centred around the generation of bespoke turbulent flows using active turbulence generating grids and investigating how turbulence influences other canonical and environmental fluids problems. His team is primarily funded via the European Research Council (Starting Grant, GLITR ), Marie Skłodowska-Curie Actions (Post-doctoral fellow, Dr. Yi Hui Tee, InMyWaves) and the Research Council of Norway (FRIPRO, WallMix; Knowledge Building Project, reSail). Jason Hearst earned his PhD in 2015 from the University of Toronto Institute for Aerospace Studies (Canada), and then worked as a post-doctoral fellow at the University of Southampton (UK) with Prof. Bharath Ganapathisubramani. He moved to NTNU in 2017 as an Associate Professor and was promoted to Professor in 2023. He is presently on sabbatical visiting the University of Oxford Environmental Fluid Mechanics Group.”

This talk is part of the Engineering Fluids Group Seminar series.

This talk is included in these lists:

• Acoustics Lab Seminars
• Board Room
• Engineering Department Acoustics/Combustion Student seminars
• Engineering Fluids Group Seminar

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