| Summary: | 碩士 === 國立虎尾科技大學 === 航空與電子科技研究所 === 100 === Unmanned aerial vehicle (UAV) coupled with comparatively low cost and flexibility, makes this type of vehicle extremely attractive. The movable high lift device and control surfaces are instead by this jet type Gurney flap for the purpose of reducing the weight and power requirement. The numerical simulation and experimental measurement is investigate the aerodynamic characteristics of jet type Gurney flap, which is developed coupling with the advantages of Gurney flap and jet flap, applied on the UAV. The effects of the configuration parameters, installation arrangement, and operation mode of this jet type Gurney flap on the wing under different flight conditions will be discussed in detail for the flow structure, aerodynamic, control and stealth properties. In experiments wind tunnel investigation was undertaken to effects of Gurney flap on a wing, the result of life and drag between the experimental and numerical simulation is in the range 10-20%.
This research utilizes 2D and 3D turbulent numerical simulation to study aerodynamic characteristics of a Gurney flap, jet flap, perforate Gurney flap, T-strip and combined jet and Gurney flap on a NACA 4412 airfoil at Re = 3×106 and M∞ = 0.2. The 2D results show the lift is increase as the flap height is increase for the Gurney flap, the maximum enhancement of the Cl is 174.3% as 0.5≦Lh≦4%, 0≦Sf≦10% and 0°≦θf≦180°. For the jet flap, the maximum enhancement of the Cl is 165.5% as 0.005≦Cμ≦0.02, 0≦Sj≦10% and 0°≦θj≦180°. For the perforate Gurney flap, the maximum enhancement of the Cl is 1.63% and the maximum decrease of the Cd is 16.87% as 0≦Nh≦3. For the T-Strip, the lift curve slope and maximum Cl is increase with flap height. However, the drag is also growth apparently. For the combined jet and Gurney flap, the case of a jet flow just under Gurney flap has the best lift coefficient. Besides, it is found that a proper combination of flap height and jet flow momentum can reduce the drag for the case of Gurney flap and the energy supply for the case of Jet flap under the similar aerodynamic requirement. The 3D results show the lift is increase as the flap height is increase for the Gurney flap, the maximum enhancement of the Cl is 109.89% as 0.5≦Lh≦4%, 0≦Rf≦1 and different installed position. For the perforate Gurney flap, the maximum enhancement of the Cl is 1.54% and the maximum decrease of the Cd is 6.31% as 0≦Rf≦1 and 0≦Nh≦3. For the jet flap, the maximum enhancement of the Cl is 159.4% as 0.005≦Cμ≦0.02, 0≦Rj≦1 and different installed position. For the combined jet and Gurney flap, change the relation position, the effect of the different relation position upon the plane wing is as similar as 2D result.
The RCS results show the installation of the Gurney flap at the trailing edge, no significant difference relative no flap and reduced relative the installation of the traditional flap.
The correlation for the practical design parameters with the jet and Gurney flap performances is established. This study also investigates the physical mechanism of high lift applied on the wing. The key points regarding the UAV system design and environment control can be provided the future reference for engineers designing such a system.
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