The aim of this dissertation is to contribute to a better comprehension of the mechanism of flapping airfoils/wings propulsion and the associated unsteady aerodynamics, independently of their possible practical applications. We describe an accurate and stable numerical method to numerically solve the incompressible Navier-Stokes equations, which, used together with the overlapping grids method and to the numerical tools implemented, constitutes a very powerful tool to solve fluid dynamics problems with fixed and moving/deforming boundaries in two and three space dimensions. The two-dimensional results are presented for airfoils undergoing heaving and coupled heaving-and-pitching motion. The interest here is to determine the values of flapping frequency and flapping amplitude best suited for flapping flight, in terms of maximum propulsive efficiency and thrust production. We also study the influence of airfoil cambering and airfoil flexibility on the aerodynamic performance. Finally, three-dimensional rigid finite-span wings undergoing heaving, coupled heaving-and-pitching and root-flapping motion modes are investigated, with focus on the wake topology and aerodynamic performance, and their dependence on the flapping motion parameters. We also establish the best criteria for vortical structures identification and assess whether the assumption of two-dimensionality has some validity in three-dimensional cases.

• Front cover - Table of contents - Abstract
• Chapter 1. Introdution
• Chapter 2. Aerodynamics of flapping flight
• Chapter 3. Governing equations of fluid dynamics
• Chapter 4. On structured overlapping grids
• Chapter 5. Numerical method
• Chapter 6. Validation and verification
• Chapter 7. Wake structures and aerodynamic performance of flapping airfoils
• Chapter 8. Wake topology and aerodynamic performance of finite-span flapping wings
• Chapter 9. Conclusions and perspectives
• Appendix - Bibliography

• Download the whole thesis in one single file (the file is approximately 86 MB)

• Guerrero, J. "Numerical simulation of the unsteady aerodynamics of flapping flight." PhD Thesis, University of Genoa, Italy. 2009.

Heaving airfoils

• St = 0.15, h = 0.30, Re = 1100
• St = 0.30, h = 0.15, Re = 1100
• St = 0.30, h = 0.35, Re = 1100
• St = 0.40, h = 0.40, Re = 1100
• St = 0.50, h = 0.20, Re = 1100
• St = 0.50, h = 0.30, Re = 1100
• St = 0.60, h = 0.10, Re = 1100
• St = 0.60, h = 0.40, Re = 1100


• St = 0.90, h = 0.45, Re = 1100 (jet-switching wake)
• St = 0.90, h = 0.375, Re = 1100 (jet-switching wake)
• St = 1.20, h = 0.60, Re = 1100 (jet-switching wake)

Heaving and pitching airfoils

• St = 0.20, h = 0.40, pitching angle = 5 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.20, h = 1.0, pitching angle = 10 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.20, h = 1.0, pitching angle = 20 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.20, h = 0.40, pitching angle = 30 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.20, h = 0.60, pitching angle = 40 degrees, phase angle = 90 degrees, Re = 1100


• St = 0.30, h = 1.0, pitching angle = 5 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.30, h = 1.4, pitching angle = 15 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.30, h = 1.0, pitching angle = 25 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.30, h = 1.2, pitching angle = 30 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.30, h = 0.40, pitching angle = 40 degrees, phase angle = 90 degrees, Re = 1100


• St = 0.40, h = 0.40, pitching angle = 5 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.40, h = 0.40, pitching angle = 20 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.40, h = 1.0, pitching angle = 20 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.40, h = 1.0, pitching angle = 30 degrees, phase angle = 90 degrees, Re = 1100
• St = 0.40, h = 2.0, pitching angle = 50 degrees, phase angle = 90 degrees, Re = 1100


• St = 0.25, h = 0.25, pitching angle = 10 degrees, phase angle = 85 degrees, Re = 1100
• St = 0.25, h = 0.25, pitching angle = 10 degrees, phase angle = 95 degrees, Re = 1100
• St = 0.25, h = 0.25, pitching angle = 10 degrees, phase angle = 105 degrees, Re = 1100

Heaving cambered airfoils

• St = 0.30, h = 0.10, NACA 2212 airfoil, Re = 1100
• St = 0.30, h = 0.30, NACA 4412 airfoil, Re = 1100
• St = 0.30, h = 0.30, NACA 6612 airfoil, Re = 1100
• St = 0.40, h = 0.10, Selig 1223 airfoil, Re = 1100
• St = 0.40, h = 0.30, Selig 1223 airfoil, Re = 1100

Heaving flexible airfoils

• St = 0.30, h = 0.25, max. flexure = 0.0 (rigid case), Re = 1100
• St = 0.30, h = 0.25, max. flexure = 0.1, Re = 1100
• St = 0.30, h = 0.25, max. flexure = 0.3, Re = 1100
• St = 0.30, h = 0.25, max. flexure = 0.5, Re = 1100

Note:

• St = Strouhal number
• h = amplitude
• Re = aReynolds number

Heaving wings (aspect ratio = 2)

• St = 0.20, f = 1.0, Re = 250 - Top view
• St = 0.20, f = 1.0, Re = 250 - Side view
• St = 0.20, f = 1.0, Re = 250 - Perspective view


• St = 0.30, f = 1.0, Re = 250 - Top view
• St = 0.30, f = 1.0, Re = 250 - Side view
• St = 0.30, f = 1.0, Re = 250 - Perspective view


• St = 0.40, f = 1.0, Re = 250 - Top view
• St = 0.40, f = 1.0, Re = 250 - Side view
• St = 0.40, f = 1.0, Re = 250 - Perspective view


• St = 0.20, f = 0.50, Re = 250 - Top view
• St = 0.20, f = 0.50, Re = 250 - Side view
• St = 0.20, f = 0.50, Re = 250 - Perspective view


• St = 0.30, f = 0.50, Re = 250 - Top view
• St = 0.30, f = 0.50, Re = 250 - Side view
• St = 0.30, f = 0.50, Re = 250 - Perspective view


• St = 0.40, f = 0.50, Re = 250 - Top view
• St = 0.40, f = 0.50, Re = 250 - Side view
• St = 0.40, f = 0.50, Re = 250 - Perspective view

Rolling wings - Root flapping wings (aspect ratio = 2)

• St = 0.15, f = 1.0 , Re = 250 - Top view
• St = 0.15, f = 1.0 , Re = 250 - Side view
• St = 0.15, f = 1.0 , Re = 250 - Front view
• St = 0.15, f = 1.0 , Re = 250 - Perspective view


• St = 0.35, f = 1.0 , Re = 250 - Top view
• St = 0.35, f = 1.0 , Re = 250 - Side view
• St = 0.35, f = 1.0 , Re = 250 - Front view
• St = 0.35, f = 1.0 , Re = 250 - Perspective view


• St = 0.40, f = 1.0 , Re = 250 - Top view
• St = 0.40, f = 1.0 , Re = 250 - Side view
• St = 0.40, f = 1.0 , Re = 250 - Front view
• St = 0.40, f = 1.0 , Re = 250 - Perspective view


• St = 0.50, f = 1.0 , Re = 250 - Top view
• St = 0.50, f = 1.0 , Re = 250 - Side view
• St = 0.50, f = 1.0 , Re = 250 - Front view
• St = 0.50, f = 1.0 , Re = 250 - Perspective view


• St = 0.40, f = 0.50 , Re = 250 - Top view
• St = 0.40, f = 0.50 , Re = 250 - Side view
• St = 0.40, f = 0.50 , Re = 250 - Front view
• St = 0.40, f = 0.50 , Re = 250 - Perspective view

Note:

• St = Strouhal number
• f = frequency
• Re = aReynolds number

Articles

• A. Bottaro, J. Favier, J. Guerrero, D. Venkataraman, H. Wedin, "Sulla Scia di Icaro," Sapere, anno 75, numero 5(1064), pp. 66-77, Oct. 2009. https://hal.archives-ouvertes.fr/hal-01073987
• J. Guerrero, "Effect of Cambering on the Aerodynamic Performance of Heaving Airfoils," Journal of Bionic Engineering, vol. 6, Issue 4, pp. 398-407, Dec. 2009. https://doi.org/10.1016/S1672-6529(08)60134-1
• J. Guerrero, "Aerodynamic Performance of Cambered Heaving Airfoils," AIAA Journal, vol. 48, no. 11, pp. 2694-2698, Nov. 2010. https://doi.org/10.2514/1.J050036
• J. Guerrero, "Wake Signature and Strouhal Number Dependence of Finite-Span Root Flapping Rigid Wings," Journal of Bionic Engineering, vol. 7, Supplement 4, pp. S109-S122, Dec. 2010. https://doi.org/10.1016/S1672-6529(09)60224-9
• J. Guerrero, "Wake Signature of Finite-Span Flapping Rigid Wings," High-Performance Computing in Science and Engineering ’10: Transactions of High-Performance Computing Center, Stuttgart (HLRS) 2010, pp. 407-427, 2011. https://doi.org/10.1007/978-3-642-15748-6_31
• J. Guerrero, "Wake topology and aerodynamic performance of heaving wings," Flight Physics – Models, Techniques and Technologies, IntechOpen, Chapter 7, Dec. 2017. http://dx.doi.org/10.5772/intechopen.71517

Conferences, research highlights, media appearances, and others

• J. Guerrero, "Overset Composite Grids for the Simulation of Complex Moving Geometries," MASCOT06 - 6th Meeting on Applied Scientific Computing and Tools, Grid Generation, Approximation and Visualization. CNR-IAC, Rome, Italy. October 05-07, 2006.
• J. Guerrero, "Efficient Treatment of Complex Geometries and Moving Bodies Using Overlapping Grids," The 10th International Society of Grid Generation (ISGG) Conference on Numerical Grid Generation. IMACS – ISGG. Crete, Greece. September 16-20, 2007.
• J. Guerrero, "CFD Study of Biologically Inspired Flapping/Oscillating Foils in Forward Motion," 1st Peer Training Meeting on Applied Scientific Computing and Tools. CNR-IAC, Rome, Italy. October 21-22, 2008.
• J. Guerrero, "Algebraic Multigrid Methods on Overlapping Grids," MASCOT08 - 8th Meeting on Applied Scientific Computing and Tools, Grid Generation, Approximation and Visualization. CNR-IAC, Rome, Italy. October 23-25, 2008.
• J. Guerrero, "Numerical Simulation of the Unsteady Aerodynamics of Flapping Flight," 10th Teraflop Workshop. Applications and systems for future HPC. HLRS, Universität Stuttgart, Germany. March 16-17, 2009.
• J. Guerrero, "Wake Signature and Aerodynamic Performance of Finite-Span Root Flapping Rigid Wings," HPC-Europa2. Science and Supercomputing in Europe. Research Highlights 2009.
• J. Guerrero, "Wake Signature and Strouhal Number Dependence of Finite-Span Flapping Wings," Transnational Access Meeting (TAM 2010) HPC-Europa2. CSC-HPC-Europa2, Helsinki, Finland. June 15-17, 2010.
• J. Guerrero, "Wake Signature and Strouhal Number Dependence of Finite-Span Flapping Wings," International Conference of Bionic Engineering ICBE. Zhuhai, China. September 14-16, 2010.