The cross-sectional geometry of an insect wing has historically been simplified to a rectangular, elliptic, or having a streamlined airfoil shape. Up until this point, no analysis has utilized a morphologically accurate insect wing. As such, there remains significant questions as to whether or not there are aerodynamic benefits to the wing vein structure accompanying the already known structural improvements. The present study uses a bumblebee specimen (Bombus pensylvanicus) acquired by the author, scanned using a skyscan microCT scanner, and post-processed for computational analysis. The resulting geometry captures the naturally occurring vein structures present in the bee wing and is used to better understand aerodynamic effects of biological corrugation. The aerodynamics associated with a morphologically accurate bee wing geometry are explored in two and three dimensions for the first time. Multiple methodologies are validated with experimental results presented in the literature to capture the fluid dynamics in two dimensions including the Lattice-Boltzmann method and unstructured dynamic remeshing using a Navier-Stokes approach. The effects of wing cross-section are compared first with common geometries used in the literature in two dimensions and then between cross-sections extracted at different locations along the wing span. A three-dimensional methodology is validated and used to compare the true bee wing with one using a rectangular cross-section in symmetric hovering. The influence of spanwise cross-section is revisited in three dimensions and compared to the results found in two-dimensions for the same kinematics in forward flight. The final focus of the dissertation is the first simulation of a morphologically accurate wing using kinematics described in the literature. / PHD / Insect flight has been an area of fascination and interest, going through phases of observation, experimentation and most recently, computational analysis. The modern paradigm for computational fluid dynamics analysis of insect flight uses an accurate planform of the wing with the cross-section simplified to an airfoil, ellipse, or rectangular plate. In reality, insect wings exhibit a vein structure which yields a complex geometry. The vein system along the wing has already been proven to have structural benefits, arresting crack propagation and adding to the overall stiffness of the wing, yet the aerodynamic properties have remained notably unexplored. The present work uses a scanned three-dimensional representation of a bee wing to explore the possible influences wing cross-section has on aerodynamic performance, and establishes a validated computational methodology to do so in two and three dimensions. The presented work begins by comparing and evaluating the forces and flow field around two-dimensional representations of the true wing with cross-sections common to the literature. Based on the results from the two-dimensional cross-sectional study, there were distinct differences observed between geometries which motivated further study into geometric variation with spanwise location. The comparison across spanwise location for the true bee wing determined that there were numerous coincident structures present along the wing, lending credence to the possibility that the vein structure is also of aerodynamic benefit. The analysis then moved to three dimensions, re-investigating cross-sectional effects in hovering and then evaluating spanwise variation in two and three dimensions. The dissertation concludes with the first analysis of a true bee wing using kinematics described in the literature.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/93962 |
| Date | 31 August 2017 |
| Creators | Feaster, Jeffrey Oden |
| Contributors | Mechanical Engineering, Bayandor, Javid, Battaglia, Francine, Mueller, Rolf, Deiterding, Ralf, Socha, John J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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