Towards a General Theory of Accelerating Airfoils

with Eric Limacher, Assistant Professor
Dept. of Mechanical & Manufacturing Engineering, University of Calgary

113 McBryde Hall, 2:30 – 3:45pm, Wednesday, December 11, 2024

In the 1930s, Theodorsen and his contemporaries derived equations to predict transient forces on oscillating or accelerating airfoils, and the enduring appeal of those models lies in their simple algebraic form.  However, the limitations of those works to motions of small displacement impede their use in applications of modern interest, such as biomimetic flapping-wing flight or unsteady wind-turbine operation.  This seminar will briefly review important highlights in the century-long history of unsteady aerodynamics, demonstrating the need for a more general unsteady airfoil theory.  This will lead into a presentation of preliminary work conducted at the U of C to establish a new theoretical framework for studying accelerating foils undergoing large displacements.  This work draws on the underappreciated body of work that will be referred to as “vortical flow theory”, which expresses force in terms of continuous vorticity distributions, superseding the limitations of potential-flow techniques that underly classical treatises.

Eric Limacher is an Assistant Professor in the Schulich School of Engineering at the University of Calgary (U of C), where he teaches courses on aerodynamics and renewable energy in the Department of Mechanical and Manufacturing Engineering.  His research program explores the aerodynamics of accelerating wings, with applications to biomimetic drones and wind energy.  He is a principal investigator in the U of C’s Laboratory for Turbulence Research in Aerodynamics and flow Control (LTRAC), which houses two wind tunnels and a water channel equipped to perform particle image velocimetry (PIV).  His previous industry career involved roles as a design engineer in clean-tech startups developing run-of-river water turbines and waste-heat-to-electricity systems.