Aeroelastic Limit Cycle Oscillation (LCO) Modulation and Annihilation
Abstract
Fluid-structure interactions have been thoroughly studied since the early twentieth century with aeroelasticity comprising a significant section of that field. Recent research has included the study of aeroelastic limit cycle oscillations (LCO) and their effect of aerospace systems as well as their potential use for renewable energy harvesting. However, aeroelastic systems experiencing LCO in the presence of additional incoming flow disturbances is less well understood. The iSSRL has performed several studies which examine aeroelastic wings placed downstream of disturbance generators. These have included other wings, static bluff bodies, and variable frequency disturbance generators. The interactions between the aeroelastic systems and these upstream bodies will help gain further insight as to how incoming flow disturbance affect aeroelastic systems experiencing LCO.
Research Aims
1. Understand and map the spatiotemporal relationships between incoming flow disturbance features and the unsteady aerodynamic forces and moments generated by a wing.
2. Establish the effects of incoming flow disturbance topology, strength, frequency content, and phasing on the stability and nonlinear oscillation behavior of an aeroelastic wing.
3. Create a framework for tailoring flow disturbance profiles to produce desired aeroelastic response and demonstrate control of aeroelastic wing stability and oscillation phenomena by prescribing incoming flow disturbances in a wind tunnel experiment.
Examples
A static bluff body placed upstream of an aeroelastic wing was used to annihilate preexisting LCO in the wing. Vortices were shed by the bluff body at approximately three times the LCO frequency of the wing. This passive LCO annihilation occurs randomly and does not resume. Tests were performed in the NCSU Subsonic Wind Tunnel.
Current Researchers
Michael Hughes
Publications
Suresh Babu, A. V., Medina, A., Rockwood, M., Bryant, M., and Gopalarathnam, A., “Theoretical and Experimental Investigation of an Unsteady Airfoil in the Presence of External Flow Disturbances,” Journal of Fluid Mechanics, Vol. 921, A21, 2021.
Hughes, M., Gopalarathnam, A., Bryant, M., “Toward On-Demand Modulation and Annihilation of Aeroelastic Limit Cycle Oscillations with Dynamic Upstream Disturbance Generator,” Online Symposium on Aeroelasticity, Fluid-Structure Interaction, and Vibrations, 2021.
Hughes, M., Mook, M., Jenkins, M., SureshBabu, A. V., Gopalarathnam, A., Bryant, M., “Flow Disturbance Generators Based on Oscillating Cylinders with Attached Splitter Plates,” Proc. ASME 2021 International Mechanical Engineering Congress and Exposition, 2021.
Kirschmeier, B., Pash, G., Gianikos, Z., Medina, A., Gopalarathnam, A., and Bryant, M., “Aeroelastic inverse: Estimation of aerodynamic loads during large amplitude limit cycle oscillations,” Journal of Fluids and Structures, Vol. 98, 2020.
Kirschmeier, B., Gianikos, Z., Gopalarathnam, A., and Bryant, M., “Amplitude Annihilation in Wake-Influenced Aeroelastic Limit Cycle Oscillations,” AIAA Journal, Vol. 58, No. 9, 2020.
Gianikos, Z., Kirschmeier, B., Gopalarathnam, A. and Bryant, M., “Limit Cycle Characterization of an Aeroelastic Wing in a Bluff Body Wake” Journal of Fluids and Structures, Vol. 95, 2020.
Chatterjee, P., Jenkins, M., Suresh Babu, A. V., Medina, A., Gopalarathnam, A., and Bryant, M., “Tailored Bluff Body Motion for Generating Desired Wake Structures,” AIAA Aviation Forum, June 15-19, Online Only (due to COVID-19), 2020.
Gianikos, Z. N., Kirschmeier, B., and Bryant, M., “Limit Cycle Characterization of an Aeroelastic Airfoil in the Wake of an Upstream Bluff Body”, 2018 Applied Aerodynamics Conference, AIAA AVIATION Forum, (AIAA 2018-3485).
Funding Sources
National Science Foundation Award No. CMMI-2015983
Air Force Officer of Scientific Research Award No. FA9550-17-1-0301
