Hudzaifah, Hudzaifah (2026) Studi Numerik Pengaruh Pemasangan Riblet Segitiga Terhadap Perubahan Karakteristik Aliran pada Airfoil Simetri NACA 0026 Studi Kasus Riblet Ukuran s = h = 0,5 mm, Orientasi: Transversal, Aligment: Aligned. Other thesis, Insitut Teknologi Sepuluh Nopember.
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Abstract
Penelitian ini dilatarbelakangi kebutuhan peningkatan efisiensi aerodinamika melalui pengurangan gaya hambat tanpa mengorbankan gaya angkat, mengingat drag yang tinggi dapat meningkatkan konsumsi energi dan menurunkan rasio lift-to-drag. Studi ini menganalisis pengaruh riblet segitiga aligned (s = h = 0,5 mm) yang dipasang pada 25-30% panjang chord permukaan atas airfoil NACA 0026 menggunakan simulasi Computational Fluid Dynamics (CFD) dua dimensi pada ANSYS Fluent. Simulasi dilakukan pada kecepatan freestream (V) = 8, 12, dan 16 m/s dengan variasi sudut serang (AOA) = -15° hingga15°, serta pemilihan model turbulensi ditetapkan melalui validasi terhadap XFOIL sehingga model Transition SST memberikan deviasi terkecil sebesar 1,5%. Parameter yang dievaluasi meliputi koefisien drag (Cd), koefisien lift (Cl), rasio Cl/Cd, distribusi koefisien tekanan (Cp), kontur dan vektor kecepatan, serta turbulent kinetic energy (TKE). Hasil menunjukkan C_d minimum terjadi saat AOA 0° dan meningkat seiring AOA membesar, penambahan riblet menurunkan Cd terbatas pada V = 8 m/s namun pada V = 12 dan 16 m/s cenderung meningkatkan Cd akibat kontribusi skin friction. Cl meningkat hampir linear hingga sekitar AOA 10° lalu menurun pada AOA 15° (stall). Sedangkan efisiensi Cl/Cd maksimum terjadi pada AOA 10°, di mana riblet tidak terbukti meningkatkan Cl/Cd dengan hasil yang lebih rendah dibandingkan airfoil polos. Secara global Cp dan pola aliran makro kedua konfigurasi relatif serupa, dengan pengaruh riblet dominan lokal near-wall, tidak terbukti menunda separasi, dan perbedaan TKE mengecil pada AOA tinggi karena dominasi separasi berskala besar.
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This study numerically investigates the effect of aligned triangular riblets with a size of s = h = 0.5 mm installed at 25–30% of the upper surface chord length of a symmetric NACA 0026 airfoil on its aerodynamic characteristics. Two-dimensional CFD simulations were conducted using ANSYS Fluent with the Transition SST turbulence model. The simulations were performed at freestream velocities of 8, 12, and 16 m/s and angles of attack ranging from −15° to 15°. The evaluated aerodynamic parameters include the drag coefficient (Cd), lift coefficient (Cl), lift-to-drag ratio (Cl/Cd), pressure coefficient (Cp) distribution, velocity contours, and turbulent kinetic energy (TKE). The numerical results indicate that the riblets provide only a limited reduction in Cd at low freestream velocity (8 m/s). In contrast, at higher velocities of 12 and 16 m/s, the drag coefficient increases due to the dominance of increased skin friction effects. The lift coefficient exhibits an almost linear increase up to an angle of attack of approximately 10°, followed by a decrease under stall conditions. However, the presence of riblets does not result in a significant improvement in lift performance or overall aerodynamic efficiency (Cl/Cd). The Cp distributions and macroscopic flow patterns of both configurations remain relatively similar, suggesting that the riblet effects are confined to the near-wall region and are ineffective in delaying flow separation at high angles of attack.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Riblet, NACA 0026, CFD, Koefisien Drag, Koefisien Lift, Riblets, Drag Coefficient, Lift Coefficient |
| Subjects: | T Technology > T Technology (General) > T57.62 Simulation T Technology > TA Engineering (General). Civil engineering (General) > TA357 Computational fluid dynamics. Fluid Mechanics T Technology > TL Motor vehicles. Aeronautics. Astronautics > TL777 Details and parts of models (Including propellers) |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Hudzaifah Hudzaifah |
| Date Deposited: | 03 Feb 2026 02:44 |
| Last Modified: | 03 Feb 2026 02:44 |
| URI: | http://repository.its.ac.id/id/eprint/131936 |
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