Experimental and computational investigation of sound absorption performance of sustainable porous material: Yucca Gloriosa fiber (original) (raw)

Numerical and Experimental Simulations of Flapping Wings

International Journal of Micro Air Vehicles, 2010

This paper presents recent progress in a continuing investigation of the aeromechanical aspects of unsteady flapping wings for micro air vehicles (MAV). Numerical simulations were performed for two-dimensional (2D) pitching-plunging airfoils and three-dimensional (3D) flapping wings, mainly at hover conditions, using an in-house code called INSflow. The results were compared with available experimental data obtained in the water tunnel at the NRC-IAR. The investigation revealed that, at hover conditions, the vortices formed during the airfoil plunging motion may remain near the airfoil and affect new vortex formations, and thus the integral aerodynamic performance. In addition, the flow around the 3D insect-like wing is fully three-dimensional. The tip flow affects the flow separation, reducing the separation intensity. Two-dimensional calculations may over-predict the separation and the shedding vortices, thus affecting the generation of aerodynamic forces.

Flapping-wing aerohydromechanics in nature and engineering

Flapping wings have been the propulsion system used by birds, insects and fish for millions of years. Yet, the preferred system for aircraft and ship propulsion is the propeller or jet engine. It is the objective of this paper to show that recent interest in the development of micro air vehicles may lead to the adoption of flapping-wing propulsors as the superior system. Also, it is shown that flapping hydrofoils may have potential as effective water energy conversion devices. The knowledge gained in the aerohydromechanics of birds, insects and fish therefore may soon be applied to the design of air vehicles and power generators. Keywords: air vehicle design, hydropower generation, flapping-wing aerohydromechanics. 1 Introduction Birds, insects, fish and cetaceans use flapping wings as thrust and lift generators. Therefore, it is not surprising that the idea of adopting flapping wings for the propulsion of man-made objects was examined as early as 1490 by Leonardo da Vinci. At the e...