The results of experiments on the threshold behavior and large-amplitude oscillation of "outward-swinging door" vibrating flap valves in an air environment are reported and compared with the predictions of a simple nonlinear theory that parametrizes aerodynamic effects by means of a simple damping coefficient together with a contraction coefficient for the flow. The agreement is acceptably good...

The hypersonic aeroelastic and aerothermoelastic problem of a double-wedge airfoil typical cross-section is studied using three different unsteady aerodynamic loads: (1) third-order piston theory, (2) Euler aerodynamics, and (3) Navier-Stokes aerodynamics. Computational aeroelastic response results are used to obtain frequency and damping characteristics, and compared with those from piston the...

The enhanced aerodynamic performance of insects results from an interaction of three distinct yet interactive mechanisms: delayed stall, rotational circulation, and wake capture. Delayed stall functions during the translational portions of the stroke, when the wings sweep through the air with a large angle of attack. In contrast, rotational circulation and wake capture generate aerodynamic forc...

The singularity structure of a second-order ordinary differential equation with polynomial coefficients often yields the type solution. It is shown that $\theta$-operator method can be used as symbolic computational approach to obtain indicial and recurrence relation. Consequently, leads transformations yield solution in terms special function, if suitable. Hypergeometric Heun-type equations ar...

MEMS thermal shear-stress sensors exploit heat-transfer effects to measure the shear stress exerted by an air flow on its solid boundary, and have promising applications in aerodynamic control. Classical theory for conventional, macroscale thermal shear-stress sensors states that the rate of heat removed by the flow from the sensor is proportional to the 1/3-power of the shear stress. However, ...

Aeroacoustics, the science of noise generation and propagation through airflows, is a relatively young discipline compared to other more classical fields of mechanics. Nevertheless, it has seen tremendous progress since its foundations were laid in the form of the first overall aeroacoustic theory by Lighthill in his pioneering work in 1952. The basic understanding of aerodynamically generated ...

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft’s flexible aerodynamic surface. The aircraft models...

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...