Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 102, Issue 1 (2023) 171-183 171 Journal of Advanced Research in Fluid Mechanics and Thermal Sciences Journal homepage: https://semarakilmu.com.my/journals/index.php/fluid_mechanics_thermal_sciences/index ISSN: 2289-7879 The Aerodynamic Characteristics Investigation on NACA 0012 Airfoil with Owl’s Wing Serrations for Future Air Vehicle Muhammad Ridzwan Ramli 1 , Wan Mazlina Wan Mohamed 1,* , Hamid Yusoff 2 , Mohd Azmi Ismail 3 , Ahmed Awaludeen Mansor 2 , Azmi Hussin 2 , Aliff Farhan Mohd Yamin 2 1 Malaysia Institute of Transport (MITRANS), College of Engineering, College of Engineering, Universiti Teknologi MARA Shah Alam, 40450 Shah Alam, Selangor, Malaysia 2 Center for Mechanical Engineering Studies, Universiti Teknologi MARA, Cawangan Pulau Pinang, 13500 Permatang Pauh, Pulau Pinang, Malaysia 3 School of Mechanical Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Pulau Pinang, Malaysia ARTICLE INFO ABSTRACT Article history: Received 25 July 2022 Received in revised form 9 December 2022 Accepted 21 December 2022 Available online 8 January 2023 Owls have an incredibly unique ability to fly in silence, and this ability has significant potential to reduce noise pollution from aircraft engines. For decades, researchers have been studying the noise abatement system in conventional aircraft, but only a few of them had looked into the owl’s ability to reduce the aircraft noise level, especially on the serrated wing. The present study aims to investigate the lift and drag coefficient of the serrated wings including leading-edge serrations, trailing-edge serrations, both-edge serrations, and the original/baseline wing model from the NACA 0012 airfoil. The experimental testing was performed in a wind tunnel at Reynolds numbers of 20,000 and 40,000 and angle of attack from 2° to 30°, in 2° angle intervals. In general, the results showed that each wing model produced a similar lift and drag coefficient profiles, which were proportional to the angle of attack. At Reynolds number of 40,000, the lift coefficient increases from 0.45 to 1.5, as the angle of attack increases from 2° to 24°. Afterward, it decreased as the angle of attack exceeded 24°. According to the data, the trailing-edge serrations model showed the lowest drag coefficient at a Reynolds number of 40,000. Meanwhile, the highest lift coefficient at Reynolds number of 40,000 had been produced by the baseline wing model. This result is beneficial in reducing the noise generation produced by wing structure and at the same time enhancing aerodynamic efficiency. Keywords: Aerodynamic performance; noise reduction; silence flight; wing serrations 1. Introduction The aircraft industry has taken many years of development to achieve advanced technologies to date. In the earliest year of the emerging flying technology, the wings have only been designed in a flat shape. Then, as humans began to develop a comprehensive understanding from time-to-time, the wing with flat shape has altered into the design called airfoil shape. Airfoil is defined as the cross- sectional shape of the wing. The airfoil-shaped wing has been used as aerodynamic aids for aircraft * Corresponding author. E-mail address: wmazlina@uitm.edu.my https://doi.org/10.37934/arfmts.102.1.171183