Abstract:

The flow on solid surfaces is called the distinction of the flow to the surface due to the exposure to positive pressure caused by geometric factors or external factors. Stream separation is one of the most critical conditions affecting the performance of aircraft. The flow separation can also be defined as the border plate separation. In the low attack angles, no separation occurs in the border layer formed on the lower and upper surfaces of the wing profile. When the impact angle reaches a critical value or exceeds that value, divisions in the border layer reach dangerous levels. Because the lifting force causes sudden decreases, the flow separation is described as an unwanted condition for the performance of the aircraft and flight safety. Stream separation can occur in different critical attack angles depending on the aerodynamic design of the wing profile. Therefore, in this study, the form of the wing profile (in accordance with the aerodynamic design conditions) was changed during the flight, with the aim of achieving maximum performance in different attack angles. The study, based on the NACA 4412 wing profile, used two-dimensional calculated fluid dynamics analysis. For higher aerodynamic performance in different attack angles during the flight, two different wings profiles (NACA 4412_1 and NACA 4412_2) were obtained by changes in the NACA 4412 profile and the aerodynamic performance of the original NACA 4412 profile was compared to the two profiles obtained. Analysis was carried out between 00 and 230 for comparison. In these analyses, the lifting rate, the pulling rate and the flow separation performance parameters have been studied.  At the end of the study, the use of the NACA 4412 wing profile from 00 to 120, the NACA 4412_2 wing profile from 120 to 170 and the NACA 4412_1 wing profile from 170 in terms of attack was found appropriate to maximum aerodynamic efficiency.