Unsteady aerodynamics of plunging cambered foil at low Reynolds number

Abstract

The present work focuses on the investigation of unsteady aerodynamics of plunging cambered foil with conditions corresponding to that of a Micro Air Vehicle. The effect of non-dimensional plunge amplitude, plunging frequency and the dimensionless plunge velocity on the propulsive performance of a harmonically plunging cambered foil are studied by varying Reynolds number from 2.5 × 104 to 7.5 × 104. Further, the flow field around the foil is analysed to understand the influence of the above-mentioned parameters and the reasons behind the positive thrust force generation. It is observed that these investigated parameters remarkably influence the instantaneous force coefficients. It is also noticed that these parameters have a significant effect on the topology of the leading edge vortex which can dramatically change the aerodynamic performance of the foil. It is observed that the Reynolds number also has a significant influence on the drag-thrust transition.