Aerodynamic Analysis of Flat Plates as Lift Generating Devices for Micro Aerial Vehicles

Abstract

Abstract With the advent of Micro Aerial Vehicles (MAVs) and their widespread applications, the use of flat plate as a lift generation device has drawn utmost attention, and therefore, it needs to be investigated further. Usually, fixed wing MAVs work in the range of Reynolds number, Re = 104–105, and it is reported that a flat plate shows a better lift-to-drag ratio in this range of Re as compared to conventional airfoils. This investigation aims to understand the aerodynamic characteristics of a flat plate at low Re and its applicability on fixed wing MAVs. In this regard, a two-dimensional computational study using the Spalart-Allmaras turbulence model is conducted to observe the flow around a flat plate for Re of 4.8 × 104 and 7.6 × 104. Two flat plates having thickness ratios of 1% and 3% are considered in the present study. In each case, the trailing edge vortices are studied and the corresponding Strouhal number is calculated. The general observation is that the Strouhal number decreases with the increase of angle of attack. The flat plate with 1% thickness ratio shows a better lift-to-drag ratio than the flat plate with 3% thickness ratio. The pressure distribution along the flat plate has also been plotted and compared to that of a conventional low Re airfoil, S5010. For the Re under investigation, the difference in pressure between the suction and pressure sides is found to be higher for the flat plate at higher AoAs.