부산대학교 도서관

This work is inspired by the denticles present on the shark skin. These denticles assist in better maneuverability of sharks. The current work aims to use these riblet structures over a NACA0015 aerofoil and study its effect in uniform inflow conditions. Experiments are performed using 2D PIV (Particle image velocimetry) to study the impact of riblets over smooth aerofoil. The aerofoil is fabricated using the 3D printing method to have high precision. The experiments are done in a subsonic wind tunnel. The Reynolds number is varied from 1.2 to 7.6 × 103. Drag and flow behavior is characterized using the PIV data. The velocity and fluctuation data show variations in wake statistics for different cases. Riblets enhance the momentum flux, and better mixing is observed, thereby reducing the wake zone. The vorticity and Reynolds stress formed over the aerofoil are reduced for the ribbed case. The higher value of Reynolds stress and transverse fluctuation for smooth aerofoil shows more entrainment of the surrounding fluid into the wake region. A maximum drag reduction of 21% is obtained in the study at Re 5100. The results show a promising effect of using ribbed aerofoil and stimulate further research. [ABSTRACT FROM AUTHOR]