Computational Fluid Dynamics

Abstract

In this paper, Computational fluid Dynamics (CFD) is used to predict accurately the incremental lift due to use of passive lift -augmentation device 'Flap'. In a 2-D wing, lift at a given angle of attack can be increased by increasing camber. In aircraft design, values of Maximum Lift Coefficient (C L max ) are used to determine the take-off and landing distances, on the assumption of usage of some type of lift-enhancing device. Passive lift enhancement device, such as a trailing edge plain flap, is relevant to most of the aircraft designs except Short Take Off and Landing (STOL) However, accurate analytical solutions to complex non linear equations of aerodynamics are a far cry and one has to depend largely on support from experimental results. It is here that CFD analysis makes the task simpler. Computational study of a typical plain flap with NACA (National Advisory Committee for Aeronautics) 0012 airfoil is taken up to predict its influence on incrementing the lift during critical phases of flight at low speed. The flow analysis is done using CFD tool FLUENT 6.3 along with GAMBIT 2.2. Effect of Plain flaps on basic aerodynamic parameters such as C P , C L , C D are studied by analyzing the flow over an airfoil with plain flap. The results obtained from the analysis are compared with analytical solutions to establish the influence and relevance of flap as an effective high lift device.