Stall flutter simulations using semi-empirical models

Oct 14

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Wednesday, October 14, 2015 - 1:30pm to 3:00pm


Dr. Greg Dimitriadis Aeroelasticity and Experimental Aerodynamics Research Group (AEA) Department of Aerospace and Mechanical Engineering University of Liege

Stall flutter is an aeroelastic instability resulting from the interaction of a flexible aeroelastic structure with the dynamic stall phenomenon. Dynamic stall involves the periodic separation and re-attachment of the flow around an oscillating wing and is notoriously difficult to model using CFD. Over the years, several semi-empirical and phenomenological models of dynamic stall have been developed, particularly for use in helicopter rotors. These models have sometimes been coupled with flexible structures in order to perform aeroelastic simulations. The purpose of the present seminar is to look at such calculations and to discuss their validity. Most dynamic stall semi-empirical models are highly nonlinear and discontinuous. Within the context of aeroelastic simulations, the discontinuities require the careful detection of boundary crossing events and the resulting systems undergo complex discontinuity-induced bifurcations. However, some of these bifurcations reflect the mathematics of the dynamic stall model but not the physics of the stall flutter phenomenon. Several different modelling approaches will be considered, such as the Gormont, Gangwani and Bielawa, Leishmann-Beddoes and ONERA models.

Greg Dimitriadis is an Associate Professor in Fluid Structure Interaction and Experimental Aerodynamics at the Aerospace and Mechanical Engineering Department of the University of Liège, Belgium. He received his Master of Engineering degree in Aeronautical Engineering from Imperial College London and his PhD in Aerospace from the University of Manchester. His research interests include linear and nonlinear aeroelasticity, unsteady aerodynamics, nonlinear dynamics and bifurcation, experimental aerodynamics and system identification.