Alfansa, Muhammad Fariz (2026) Studi Numerik Pengaruh Silinder Sirkuler Sebagai Pengontrol Pasif Terhadap Kinerja Airfoil Naca-0026 “Studi Kasus Untuk Silinder Sirkuler Dengan Rasio D/T = 1,0 dan R/T = 1,66 dan 2,18”. Other thesis, Institut Teknologi Sepuluh Nopmeber.
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Abstract
Peningkatan kebutuhan energi terbarukan mendorong pengembangan teknologi turbin angin dengan efisiensi aerodinamika yang lebih baik. Salah satu faktor yang menurunkan kinerja airfoil adalah fenomena separasi aliran yang menyebabkan penurunan gaya angkat (lift) dan peningkatan gaya hambat (drag). Salah satu metode passive flow control yang dapat diterapkan adalah pemasangan silinder sirkuler di depan leading edge untuk memodifikasi karakteristik aliran. Penelitian ini bertujuan menganalisis pengaruh pemasangan silinder sirkuler terhadap distribusi tekanan, karakteristik aliran, koefisien lift (C_L), koefisien drag (C_D), dan rasio C_L/C_D pada airfoil NACA 0026. Penelitian dilakukan secara numerik menggunakan metode Computational Fluid Dynamics (CFD) dua dimensi dengan perangkat lunak ANSYS Fluent. Simulasi dilakukan pada airfoil NACA 0026 yang dipasang silinder sirkuler berdiameter 39 mm (D/T = 1,0) pada dua radius pemasangan, yaitu R/T = 1,66 (65 mm) dan R/T = 2,18 (85 mm), dengan variasi posisi stagger θ = −45°, −30°, −15°, 0°, 15°, 30°, dan 45°, kecepatan aliran bebas 8 m/s, serta angle of attack 0°. Sebelum simulasi utama dilakukan validasi model numerik dan grid independency test. Analisis meliputi distribusi koefisien tekanan (CP), distribusi kecepatan u, kontur tekanan, kontur magnitudo kecepatan, streamline, serta karakteristik gaya aerodinamika. Hasil penelitian menunjukkan bahwa penambahan silinder sirkuler mampu memodifikasi distribusi tekanan dan pola aliran di sekitar leading edge melalui mekanisme blockage effect, flow deflection, dan nozzle effect. Konfigurasi stagger θ = ±15° menghasilkan magnitudo koefisien lift dan rasio C_L/C_D terbesar, dengan C_L sebesar +0,4015 (θ = −15°) dan −0,3936 (θ = +15°) pada R = 65 mm, serta +0,4261 (θ = −15°) dan −0,4227 (θ = +15°) pada R = 85 mm. Hasil penelitian juga menunjukkan bahwa arah gaya angkat pada beberapa konfigurasi tidak sepenuhnya sesuai dengan hipotesis awal karena interaksi aliran didominasi oleh blockage effect dan flow deflection akibat celah antara silinder dan leading edge yang terlalu sempit. Meskipun seluruh konfigurasi menghasilkan nilai drag yang lebih tinggi dibandingkan plain airfoil, posisi stagger terbukti lebih dominan daripada radius pemasangan dalam menentukan karakteristik aerodinamika airfoil NACA 0026, sehingga penambahan silinder pada kondisi penelitian ini lebih efektif sebagai metode pengendalian karakteristik aliran dibandingkan sebagai metode peningkatan efisiensi aerodinamika.
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The increasing demand for renewable energy has encouraged the development of wind turbine technology with improved aerodynamic efficiency. One of the primary factors limiting airfoil performance is flow separation, which reduces lift while increasing drag. A promising passive flow control technique involves placing a circular cylinder upstream of the airfoil leading edge to modify the surrounding flow characteristics. This study aims to investigate the effects of a circular cylinder on the pressure distribution, flow characteristics, lift coefficient (CL), drag coefficient (CD), and lift-to-drag ratio (CL/CD) of a NACA 0026 airfoil. A two-dimensional numerical simulation was performed using the Computational Fluid Dynamics (CFD) method in ANSYS Fluent. A circular cylinder with a diameter of 39 mm (D/T = 1.0) was positioned upstream of the airfoil at two radial distances, R/T = 1.66 (65 mm) and R/T = 2.18 (85 mm), with stagger angles of −45°, −30°, −15°, 0°, 15°, 30°, and 45°. The simulations were conducted at a free-stream velocity of 8 m/s and an angle of attack of 0°. Numerical model validation and a grid independence study were carried out prior to the main simulations. The analyses included pressure coefficient (CP) distribution, velocity distribution, pressure contours, velocity magnitude contours, streamlines, and aerodynamic performance. The results demonstrate that the upstream circular cylinder modifies the pressure distribution and flow field around the leading edge through the combined mechanisms of blockage effect, flow deflection, and nozzle effect. The stagger configuration of θ = ±15° produced the largest lift coefficient magnitude and the highest lift-to-drag ratio, yielding CL values of +0.4015 (θ = −15°) and −0.3936 (θ = +15°) for R = 65 mm, and +0.4261 (θ = −15°) and −0.4227 (θ = +15°) for R = 85 mm. The study also revealed that the lift direction in several configurations did not fully agree with the initial hypothesis because the flow interaction was governed primarily by the blockage effect and flow deflection, caused by the narrow gap between the cylinder and the airfoil leading edge. Although all cylinder configurations increased drag compared with the plain airfoil, the stagger position was found to have a more significant influence than the radial distance on the aerodynamic characteristics of the NACA 0026 airfoil. Therefore, under the investigated conditions, the circular cylinder is more effective as a passive flow control device than as a method for improving overall aerodynamic efficiency.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Airfoil NACA 0026, Silinder Sirkuler, Passive Flow Control, Separasi Aliran, Computational Fluid Dynamics (CFD), NACA 0026 Airfoil, Circular Cylinder, Flow Separation |
| Subjects: | T Technology > TJ Mechanical engineering and machinery T Technology > TJ Mechanical engineering and machinery > TJ808 Renewable energy sources. Energy harvesting. T Technology > TJ Mechanical engineering and machinery > TJ820 Wind power T Technology > TJ Mechanical engineering and machinery > TJ828 Wind turbines |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Muhammad Fariz Alfansa |
| Date Deposited: | 04 Aug 2026 01:24 |
| Last Modified: | 04 Aug 2026 01:24 |
| URI: | http://repository.its.ac.id/id/eprint/142648 |
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