All you need is time … to model and predict dynamic stall

Abstract: Dynamic stall on airfoils is an important practical problem that affects for example rotary wing aircraft and wind turbines. It also comprises a number of interesting fundamental fluid dynamical phenomena such as unsteady flow separation, vortex formation and shedding, unsteady flow reattachment, and dynamic hysteresis. We have identified the chain of events that play a role in the stall onset and the stall recovery process through experiments using two-dimensional pitching airfoils and a scaled vertical axis wind turbine. The individual events will be characterised by their governing time-scales and flow features and recent attempts to control dynamic stall will be presented.
 

Bio: Karen Mulleners started as an assistant professor in the institute of mechanical engineering in the school of engineering at EPFL in 2016 and was recently promoted to associate professor. She is the head of the unsteady flow diagnostics laboratory (UNFoLD). She is an experimental fluid dynamicist who focusses on unfolding the origin and development of unsteady flow separation and vortex formation. Karen studied physics in Belgium (Hasselt University, previously Limburgs Universitair Centrum) and the Netherlands (TU Eindhoven). She received her PhD in mechanical engineering from the Leibniz Universität Hannover in Germany in 2010 for her work on dynamic stall on pitching airfoils that she conducted as a member of the German aerospace centre (DLR) in Göttingen.