Experimental and Computational Study of Rotational Lift Production of Insect Flapping Wing

This paper investigates the rotational lift production of translating and rotating wings within a small insect’s Reynolds number range. Using the Reynolds number 1200 of a bumblebee, three wing section profiles were studied: a circular cylinder model as a reference for a blunt body for which the well-known Magnus effect will occur, a flat plate model as a reference for a sharp body for which the Kramer effect will occur, and finally, an elliptical cylinder model as a transition case. Direct force measurement and particle image velocimetry (PIV) experiments were performed to measure the lift produced and the surrounding flow velocity, and the Kutta–Joukowski theorem was applied to analyze the PIV results. The Kutta–Joukowski theorem gives the relationship between lift and circulation on a body moving at constant speed in a real fluid with some constant density. The experimental results were analyzed and verified by comparing them to the computational results. In general, there is reasonable agreement between the experimental and computational results, confirming that the Magnus effect is observed for the circular cylinder model and no Kramer effect is observed for the flat plate model. The elliptical cylinder model does not appear to be blunt enough for the Magnus effect to occur, and it is not sharp enough for the Kramer effect to occur.