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Abstract

Present paper study aerofoil with NACA2412 with Fowler and Single Slotted flaps that were used for the purpose of numerical investigation the effect of energy adder on the trace of wake behind the proposed wing at a Reynolds number of (2x105) with multi-element flap geometry having different gap, overlap distances, and different flap deflection angle (a). This all were inspected with various angle of attack (AOA) for both types of flaps. Such as [gap = (4.3% c) &(5.3% c)] for single slotted flap, and [(overlap= -5% c with gap =1.25% c) & (overlap= 5% c with gap= 3.75% c) ]. Flap deflection is varied in the range of [20o, 35 o45 o] and the angle of attack in the range of (AOA) is [-5 o, 5 o, 10 o, 15 o]. The numerical study involves simulation to the flow behavior by using ANSYS FLUENT 15.0, the governing equation were solved in three dimensions turbulent regime with appropriate turbulent model (k - ?, SST). Using airfoil of NACA2412 for the wing section, to study the formation of wake turbulence downstream of the trailing edge under the effect of varying different variables related to the geometry of flap position relative to the wing since they form together a multi element airfoil. Present study conducted the effect of dynamic pressure, static pressure, and the kinetic energy in addition to the velocity vector and magnitude in both (x) and (y) directions. Results show that for a gap distance equal to (5.3 % c) it is not recommended to work with both higher flap deflection and angle of attack for single slotted flaps which can be used in multi-element airfoil .And the best positions of single slotted flaps are not so well defined. Hence maximum lift coefficients of single slotted flaps are very sensitive to flap position, however, and optimum configurations cannot be predicted with any degree of accuracy. For a Fowler flap it's convenient to use the combination for an angle of attack equal to (15°) with deflection angle equal to (35° and 45°). Also it was concluded for Fowler flap that as the flap deflection angle increase to a value of (45°) with the existence of an angle of attack equal to (5°) it is clearly revealed the improper combination of these two angles due to large wake vortex generated downstream of multi-element airfoil since the boundary layer that pass over main part of the airfoil.