Perpustakaan Digital ITB

A kite played a role in the early development of the aviation world. The components of a kite include the wing body, frame, bridle, and control line (tether). In playing a kite, the fluid (wind) moves relative to the kite because of the control line restraining the kite from moving freely causing aerodynamic forces. The two main parameters governing the magnitude of kite aerodynamic forces are wind speed and angle of attack. The objective of the study is to understand the influences of wind speed and angle of attack toward the aerodynamics of a kite, the force acting on the kite, and the bridle line configuration. Kite aerodynamics analysis was conducted using Computational Fluid Dynamics (CFD) simulation modeling with finite volume method, followed by theoretical analysis, and comparison with previous research. The geometry model is a diamond shaped flat plate resembling a kite. The mesh type used for simulation was hexahedron type. Mesh convergence test was also employed to ensure the validity of the simulation. The turbulence model that was used for simulation was SST k-omega. The aerodynamic forces generate the resultant force (combination of lift and drag forces) acting on kite. The results show that the presence of a critical angle of attack influences the relationship between aerodynamic forces and angle of attack. The lift force increased until the critical angle of attack was 45-degree, which the kite then experienced a stall phenomenon (reduction of lift). The minimum relative velocity of kite to fly was found to be 10 m/s for maximum angle of attack 75-degree and 8 m/s for maximum 70-degree angle of attack. By using extrapolation, it is found that approximately 82-degree angle of attack exhibit zero lift. It is recommended to use a 30-degree angle of attack and maintain 8 m/s relative velocity to achieve stable playing style.