טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentSegev Yair
SubjectLift Generation by Flapping Wings in Hover
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Gil Iosilevskii
Full Thesis textFull thesis text - English Version


Abstract

                Lift generation by flapping wings has been a central topic of research in unsteady aerodynamics for over half a century. Early research in insect flight attempted to explain and quantify their performance using quasi-steady analysis of aerodynamic properties. With increased understanding of the importance of non-steady effects (such as leading edge separation or lift build-up time), later models resorted to unsteady methods. These included limited analytic models, numerical vortex methods of varying complexity, and, recently, CFD analyses.

The common denominator of both early and more recent research is the calculation of aerodynamic properties using prescribed wing motion - the position and attitude of the wings are assumed to be known functions of time. The problem with this approach is that it does not take into account possible morphological and physiological limitations on generating that motion. For example, the pitching motion of the wing is only a passive torsional response to aerodynamic and inertial loads; hence, it cannot follow all prescribed profiles.

We propose an alternative approach, in which the motion of the wing is a consequence of prescribed root moments, which comply with all pertinent morphological and physiological limitations. We present the differences between the two approaches, and analyze the effects of various morphological parameters on the efficiency of a hovering insect. We show that the proposed approach is able to predict the hovering capability of insects. We further show that it is possible to optimize the attainable motions using only a few parameters - a feat which cannot be achieved with the traditional approach.