Nonlinearity of the Aerodynamic Characteristics of NACA0012 Aerofoil at Low Reynolds Numbers

Unsteady Aerodynamic Performance of Model Wings at Low Reynolds Numbers

The synthesis of a comprehensive theory of force production in insect flight is hindered in part by the lack of precise knowledge of unsteady forces produced by wings. Data are especially sparse in the intermediate Reynolds number regime (10<Re<1000) appropriate for the flight of small insects. This paper attempts to fill this deficit by quantifying the time-dependence of aerodynamic forces for...

Unsteady aerodynamic models for agile flight at low Reynolds numbers

The goal of this work is to develop low-order models for the unsteady aerodynamic forces on a small wing in response to agile maneuvers and gusts. In a previous study, it was shown that Theodorsen’s and Wagner’s unsteady aerodynamic models agree with force data from DNS for pitching and plunging maneuvers of a 2D flat plate at Reynolds numbers between 100 and 300 as long as the reduced frequenc...

Aerodynamic loads on cactus-shaped cylinders at low Reynolds numbers

Direct numerical simulations of flow past cactus-shaped cylinders are performed at Reynolds numbers of 20, 100, and 300. The results are contrasted to those from smooth cylinders at the same Reynolds numbers. The cavities in the cactus-shaped cylinders are seen to reduce the forces acting on them. At Reynolds number of 20, the drag is reduced by 22% due to reduction in the viscous forces. At Re...

Flow-Control Effectiveness of Convergent Surface Indentations on an Aerofoil at Low Reynolds Numbers

The Effects of Wing Rotation on Unsteady Aerodynamic Performance at Low Reynolds Numbers

The downstroke-to-upstroke transition of many insects is characterized by rapid wing rotation. The aerodynamic consequences of these rapid changes in angle of attack have been investigated using a mechanical model dynamically scaled to the Reynolds number appropriate for the flight of small insects such as Drosophila. Several kinematic parameters of the wing flip were examined, including the sp...