Author : Amala AȦ, Srinivasa Rao P

The UAVs in modern days are subjected to a large operating ranges and wide environmental conditions. The tremendous changes in the wing design of UAVs in recent times lead to high lift generating wings. A clefted wing with NACA 2412 airfoil is designed and tested in the wind tunnel under subsonic flow conditions. The investigations revealed that a considerable increase in the aerodynamic performance of the wing and it can be achieved with the Clefted wing under subsonic flow conditions. In comparison with the wing section of NACA2412 clefted wing is generating improved lift. However the aerodynamic heating is going to limit the flight conditions considerably. In this paper we study numerically the thermal stability of the clefted wing under both transonic and supersonic flow conditions. The thermal stresses generated under subsonic flows are compared with the experimental values and the supersonic flight thermal behaviour is estimated using CFD. The heat transfer analysis is performed for 1 ͯ10⁸ < Grashoff Number (Gr) < 5ͯ10⁸ on the wing leading edge. Geometric effects surrounding the leading edge are investigated in order to understand its influence on heat transfer and thermal stresses. It is found that the internal thermal stress distribution is finely dependents upon Gr, as the increase in the depth of the cleft is increasing. It is also found that the clefted wing is more sensitive for the thermal loads than the normal NACA series wings.

Keywords:  Wing, Airfoil Analysis, UAVs and Low Reynolds Number flows

Article published in International Conference on Advances in Mechanical Sciences 2014, Special Issue-2 (Feb 2014)