High-Fidelity Simulations of a Flexible Flapping Wing in Forward Flight

Flapping flight is commonly used in nature at low Reynolds numbers. This work investigates the physical aspects of forward flight for flapping unmanned aerial systems. The kinematics discussed in this work is based on an anticlockwise eight-shaped flapping cycle. First the complex aerodynamic structures and their evolution (leading edge and trailing edge vortices) are presented. Then, the typical mechanisms for generating the lift and thrust are discussed with emphasis on the unsteadiness of the flow features during both the downstroke and upstroke phases. The inhomogeneity of the wing in terms of mass distribution is studied for the rigid case and it is shown that a higher density at the wing root is beneficial in respect to the mechanical power required to achieve the forward flight. The assumption of rigid wing is then removed and the elastic deformation and its effects are investigated. The relative importance of inertial/aerodynamic effects is assessed with the inclusion of structural geometric nonlinearities.

[1]  D. Tafti,et al.  Effect of Stroke Deviation on Forward Flapping Flight , 2012 .

[2]  Miguel R. Visbal,et al.  Unsteady vortex structure over a delta wing , 1994 .

[3]  Miguel R. Visbal,et al.  Origin of computed unsteadiness in the shear layer of delta wings , 1995 .

[4]  Adrian L. R. Thomas,et al.  Leading-edge vortices in insect flight , 1996, Nature.

[5]  Raymond E. Gordnier,et al.  Aeroelastic Simulations of an Aspect Ratio Two Flexible Membrane Wing , 2012 .

[6]  Peretz P. Friedmann,et al.  Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight , 2011 .

[7]  Miguel R. Visbal,et al.  High-Order-Accurate Methods for Complex Unsteady Subsonic Flows , 1999 .

[8]  Miguel R. Visbal,et al.  On the use of higher-order finite-difference schemes on curvilinear and deforming meshes , 2002 .

[9]  Chongam Kim,et al.  Aerodynamic Effects of Structural Flexibility in Two-Dimensional Insect Flapping Flight , 2011 .

[10]  Jin-Ho Kim,et al.  Computational Investigation of Three-dimensional Unsteady Flowfield Characteristics around Insects' Flapping Flight , 2011 .

[11]  K. Bathe.  Conserving energy and momentum in nonlinear dynamics: A simple implicit time integration scheme , 2007 .

[12]  Danesh K. Tafti,et al.  Effect of Wing Flexibility on Lift and Thrust Production in Flapping Flight , 2010 .

[13]  Miguel R. Visbal,et al.  A high-order flow solver for deforming and moving meshes , 2000 .

[14]  Peretz P. Friedmann,et al.  Approximate Aeroelastic Modeling of Flapping Wings: Comparison with CFD and Experimental Data , 2010 .

[15]  Miguel R. Visbal,et al.  Further development of a Navier-Stokes solution procedure based on higher-order formulas , 1999 .

[16]  Chih-Ming Ho,et al.  Unsteady aerodynamics and flow control for flapping wing flyers , 2003 .

[17]  J. P. Whitney,et al.  Effect of flexural and torsional wing flexibility on lift generation in hoverfly flight. , 2011, Integrative and comparative biology.

[18]  Peter J. Attar,et al.  High-fidelity aeroelastic computations of a flapping wing with spanwise flexibility , 2011 .

[19]  T. Daniel,et al.  The Journal of Experimental Biology 206, 2979-2987 © 2003 The Company of Biologists Ltd , 2022 .

[20]  J. Usherwood,et al.  The aerodynamics of revolving wings I. Model hawkmoth wings. , 2002, The Journal of experimental biology.

[21]  Philip E. Morgan,et al.  An Implicit LES Approach Based on High-order Compact Differencing and Filtering Schemes (Invited) , 2003 .

[22]  Miguel R. Visbal,et al.  Investigation of aspect ratio and dynamic effects due to rotation for a revolving wing using high-fidelity simulation , 2013 .