We used a dynamically scaled mechanical model of the fruit fly Drosophila melanogaster to study how changes in wing kinematics influence the production of unsteady aerodynamic forces in insect flight. We examined 191 separate sets of kinematic patterns that differed with respect to stroke amplitude, angle of attack, flip timing, flip duration and the shape and magnitude of stroke deviation. Ins...

A growing body of evidence indicates that a majority of insects experience some degree of wing deformation during flight. With no musculature distal to the wing base, the instantaneous shape of an insect wing is dictated by the interaction of aerodynamic forces with the inertial and elastic forces that arise from periodic accelerations of the wing. Passive wing deformation is an unavoidable fea...

Insect wings are deformable structures that change shape passively and dynamically owing to inertial and aerodynamic forces during flight. It is still unclear how the three-dimensional and passive change of wing kinematics owing to inherent wing flexibility contributes to unsteady aerodynamics and energetics in insect flapping flight. Here, we perform a systematic fluid-structure interaction ba...

The recent development of the world’s rst robotic insect capable of vertical takeo at the Harvard Microrobotics Lab has sparked research e orts into devising similar vehicles capable of untethered ight. The vehicle design has been extended in simulation to use one actuator per wing to produce sinusoidal apping motion in a plane. This work proposes employing a generic triangular wave to generate...

The behavior of rope-guided conveyances is so complicated that the rope-guided hoisting system hasn't been understood thoroughly so far. In this paper, with user-defined functions loaded, ANSYS FLUENT 14.5 was employed to simulate lateral motion of rope-guided conveyances in two typical kinds of shaft layouts. With rope-guided mine elevator and mine cages taken into account, results show that t...

Significant developments in bridge aeroelastic analysis have been made utilizing realistic aerodynamic force modeling for bridges with bluff sections under turbulent winds. With these developments as a background, this paper highlights state-of-the-art developments in the aeroelastic analysis and identifies new frontiers in aerodynamic tailoring of long span bridges. Challenges in the aeroelast...

Flow visualization and aerodynamic force measurements were conducted in order to investigate the flow phenomena around the wing of a hovering dragonfly. Two pairs of 4-bar linkage mechanisms were installed in a flapping model and driven by a stepping motor. The foreand hindwing have a phase difference angle of 180°. The stroke amplitude, pitch angle and incidence angle of the model were 75°, 0-...

During slow flight, bird species vary in their upstroke kinematics using either a 'flexed wing' or a distally supinated 'tip-reversal' upstroke. Two hypotheses have been presented concerning the function of the tip-reversal upstroke. The first is that this behavior is aerodynamically inactive and serves to minimize drag. The second is that the tip-reversal upstroke is capable of producing signi...

In the analysis of flexible flapping wings of insects, the aerodynamic outcome depends on the combined structural dynamics and unsteady fluid physics. Because the wing shape and hence the resulting effective angle of attack are a priori unknown, predicting aerodynamic performance is challenging. Here, we show that a coupled aerodynamics/structural dynamics model can be established for hovering,...

We present experiments and simulations of plunging maneuvers large amplitude, for velocity ratios 2, defined as the ratio between peak plunge freestream velocity. explore effect airfoil shape by considering a NACA 0012 wing flat plate. The are performed with wings aspect 4 4.86, whereas using model an infinite-aspect-ratio wing. report time evolution force coefficients flow visualizations. A go...