Numerical Study of Transversal 0.5 mm Triangular Riblet on Airfoil NACA 0026 in Increasing Lift Force and Reducing Drag Force

Abstract:

Riblet as a passive boundary layer control has attracted many researchers since it is small but has significant effect in increasing turbulence, reducing drag force, and increasing lift force. Numerical study has been performed for triangular riblet with a dimension of s = h = 0.5 mm on the upper surface of NACA 0026 airfoil with cord length 200 mm. Relative size of riblet (h+) will be 19.6. The simulation was performed at a velocity of 8, 12 and 16 m/s, which corresponds with Reynolds number 1. x 105 until 2. x 105, with variations in angles of attack of –15°, –10°, –5°, 0°, 5°, 10° and 15°. Riblet’s orientations are transversal with its alignment: protruded, aligned and indented. Simulation results showed that riblet at 8 m/s velocity were able to reduce drag force at high angle of attack, but its lift force is lower than plain airfoil. Lower lift force in airfoil is caused by turbulent kinetic energy reduction caused by riblet, especially at near wall area. At high velocity, 16 m/s, protruded and indented riblet has higher lift force, especially at angle of attack above 5°. The lift force increase in airfoil is caused by higher relative velocity for freestream velocity of 16 m/s. Better performance for 0.5 mm riblet will be obtained if riblet orientation is indented or protruded with freestream velocity at 16 m/s.

• Periodical: Engineering Headway (Volume 38)
• Pages: 227-232
• DOI: https://doi.org/10.4028/p-0FkCg2
• Online since: June 2026
• Authors: Nur Ikhwan*, Sutardi Sutardi, Triyogi Yuwono
• Keywords: Airfoil, Aligned, Computational Fluid Dynamics, Drag Reduction, Indented, NACA 0026, Protruded, Transversal, Triangular Riblet

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