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Computational Aeroelasticity

Current work: Aeroelasticity of Flexible, Biomimetic Structures

Objectives

• Understand the nonlinear dynamics, stability, and control of various biomimetic flapping wing designs featuring
• Analysis of wing flexibility
• Consideration of wing mass
• Non-naïve averaging methods
• Primary focus area: determine the influence of wing flexibility on the stability of flapping wing designs and optimal stiffness, mass, and wing loading for aerodynamic performance and stability
• Develop robust nonlinear control strategies for this nonlinear, time periodic system across the entire flight envelope

Approach - Multi-fidelity Analysis

Motivation - Bumblebees

 
exhibits significant chordwise flexibility (2)
 
• Can hover or sustain forward flight at high advance ratios
• Maintains trajectory in unsteady wind conditions
• Exhibits rapid accelerations and decelerations
• Can carry loads exceeding their body weight

Achievements

•Developed full multi-body mathematical model for multiple winged insects/vehicles from first principles and verified the result against other models in the literature
•Developed aerodynamic pitching moment predictions based on both unsteady aerodynamic theory and full direct numerical simulation of the incompressible Navier Stokes equations
•Implemented a fully coupled open loop flight dynamic solver with multiple aerodynamic models

Future Work

• Fully coupled CFD-CSD-EOM solver
• Stability analysis using advanced techniques
• Nonlinear control implementation
• Model free control development

Researchers 

• Dr. Chang-kwon Kang, Assistant Professor, MAE
• Ph.D. Student: Major James E. Bluman, P.E.
   more info here

Current Results - to be presented at AIAA SciTech in January 2016 (abstract pending acceptance)

Effects of Wing Mass on Dynamic Simulation 

These figures show that the inclusion of wing mass in the multi-body simulation has a significant effect on the longitudinal dynamic response of the body/fuselage to the high frequency forcing of the flapping wings
(m = 0 denoted wing mass omitted; m = 1 denotes full wing mass included in the simulation).


Key References

1. Kang, C. and Shyy, W., Scaling law and enhancement of lift generation of an insect-size hovering flexible wing,” Journal of Royal Society Interface, Vol. 10 no. 85, 2013
2. Sridhar, M. K., and Kang, C., “Aerodynamic Performance of Two-Dimensional, Chordwise Flexible Flapping Wings at Fruit Fly Scale in Hover Flight,” Bioinspiration & Biomimetics, Vol. 10, Nr. 3, 2015, p. 036007.
3. Liu, H., Nakata, T., Gao, N., Maeda, M., Aono, H., and Shyy, W., “Micro Air Vehicle-Motivated Computational Biomechanics in Bio-Flights:
Aerodynamics, Flight Dynamics and Maneuvering Stability,” Acta Mechanica Sinica, Vol. 26, Nr. 6, 2010, pp. 863–879.
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