EarthFlows Seminar: Directed percolation transition to turbulence
There will be a seminar in the Earth Flows research group the 15th of February. Our invited speaker is Björn Hof from Institute of Science and Technology, Austria. All interested in the topic of the seminar are welcome.
Seminar in Earth Flows / Invited Lecturer
Title: Directed percolation transition to turbulence
Speaker: Björn Hof, Institute of Science and Technology, Austria
Time and place: 15 February, 12:15 PM, PGP seminar room (FV 414), 4. floor, Physics building
The transition to turbulence in simple shear flows (e.g. pipe, channel and Couette flow) has remained an open problem for over a century. Typically here turbulence arises despite the linear stability of the laminar flow and results from perturbations of finite amplitude. Turbulence at first appears in the form of localised patches (e.g. puffs, spots or stripes) which coexist with laminar flow, resulting in complex, disordered flow patterns (spatio-temporal intermittency). Individual turbulent domains can collapse or they can proliferate and seed other patches of turbulence. The time scales on which flows evolve are extremely large and likewise are the relevant length scales.
Characterizing the transition process hence requires experiments of very large aspect ratios and extremely long observation times. In detailed experiments and direct numerical simulations of Couette flow we could for the first time determine the critical exponents that characterize this transition and show that it falls into the directed percolation universality class.
All interested are welcome to the seminar
About the Research Group - EarthFlows
The cross-disciplinary research group EarthFlows is a strategic initiative selected by the Faculty of Mathematics and Natural Sciences at the University of Oslo, and includes participants from the Department of Geosciences, Department of Physics, and Department of Mathematics at the University of Oslo.
The reserach group is hosted by the Department of Geosciences, see more details for the group here: