Afif, Muhammad Ikhsan Khairul Afif (2026) Studi Eksperimental Aliran Melewati Silinder Sirkular dengan Penempatan Pelat Splitter pada bagian Upstream dan Downstream “Studi Kasus Panjang, Ketebalan Plat Splitter, Dan Kecepatan Inlet”. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Aliran fluida yang melintasi benda tumpul (bluff body), seperti silinder sirkular, secara alami menghasilkan gaya hambat (drag) yang signifikan akibat separasi aliran dan terbentuknya daerah wake yang lebar. Fenomena ini relevan dalam berbagai aplikasi rekayasa seperti platform offshore dan tiang turbin angin. Penelitian ini bertujuan untuk menginvestigasi secara eksperimental dan numerik pengaruh variasi panjang (L/D = 1 dan 1,5) serta ketebalan (T/D = 0,08 dan 0,14) dari splitter plate ganda di depan dan belakang silinder sirkular dengan diameter (D) 36 mm, dengan bilangan Reynolds (Re) 1,2 x 10^4 dan 2,4 x 10^4. Eksperimen dilakukan dalam sub-sonic wind tunnel tipe sirkuit terbuka sedangkan simulasi numerik dilakukan pada kondisi unsteady menggunakan komputasi ANSYS Fluent berbasis model turbulensi k- ω Shear Stress Transport (SST). Hasil penelitian menunjukkan bahwa seluruh variasi penambahan splitter plate ganda mampu menaikkan nilai base pressure coefficient (Cbp), mempersempit lebar wake, serta ecara efektif menurunkan nilai koefisien drag (CD) dibandingkan dengan silinder tunggal. Konfigurasi paling optimal dicapai oleh variasi splitter plate panjang L = 1,5D dan tebal T = 0,14D pada bilangan Reynolds 2,4 x 10^4. Pada konfigurasi tersebut, metode eksperimen mencatat kenaikan nilai Cbp hingga -0,932 dengan penundaan sudut separasi (separation angle) yang signifikan mencapai 115° dari kondisi awal silinder tunggal sebesar 85°. Berdasarkan analisis numerik pada parameter optimal yang sama, integrasi tekanan permukaan menghasilkan nilai coefficient drag pressure (Cdp) terkecil dengan persentase reduksi Cdp maksimum mencapai 43,46%. Lebih lanjut, hasil visualisasi kontur kualitatif menunjukkan bahwa perpanjangan dan penebalan pelat pengganggu terbukti menekan interaksi langsung antar lapisan geser (shear layers), mereduksi intensitas fluktuasi turbulensi (turbulent intensity), serta menunda pelepasan pusaran (vortex shedding) ke arah downstream yang ditandai dengan penurunan nilai bilangan Strouhal (St) hingga di angka 0,118. Keselarasan tren yang diperoleh antara metode eksperimen dan numerik memvalidasi efektivitas tinggi metode kontrol aliran pasif ini dalam mereduksi gaya drag aerodinamika.
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Fluid flow past a bluff body, such as a circular cylinder, naturally generates significant drag due to flow separation and the formation of a wide wake region. This phenomenon is relevant in various engineering applications, such as offshore platforms and wind turbine towers. This research aims to experimentally and numerically investigate the effect of varying the length (L/D = 1 and 1.5) and thickness (T/D = 0.08 and 0.14) of dual splitter plates (upstream and downstream) on of a circular cylinder with a diameter (D) of 36 mm at Reynolds numbers (Re) of 1.2 x 10^4 and 2.4 x 10^4. The experiment was conducted in an open-circuit sub-sonic wind tunnel, while the numerical simulation was performed under unsteady conditions using ANSYS Fluent computations based on the k-ω Shear Stress Transport (SST) turbulence model. The results of the study show that all variations of adding dual splitter plates can increase the base pressure coefficient (Cbp) value, narrow the wake width, and effectively reduce the drag coefficient (CD) value compared to a single cylinder. The most optimal configuration is achieved by the splitter plate variation with a length of L = 1.5D and a thickness of T = 0.14D at a Reynolds number of 2.4 x 10^4. In this configuration, the experimental method records an increase in the Cbp value up to -0.932, with a significant delay in the separation angle reaching 115° from the initial single cylinder condition of 85°. Based on numerical analysis of the same optimal parameters, surface pressure integration yields the smallest pressure drag coefficient (Cdp) value, with a maximum Cdp reduction percentage reaching 43.46%. Furthermore, the qualitative contour visualization results show that the lengthening and thickening of the disturbance plates are proven to suppress direct interaction between shear layers, reduce the turbulence fluctuation intensity (turbulent intensity), and delay vortex shedding toward the downstream direction, which is characterized by a by a decrease in the Strouhal number (St) to 0.118. The consistency of the trends obtained between the experimental and numerical methods validates the high effectiveness of this passive flow control method in reducing aerodynamic drag force.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Reduksi Gaya Hambat, Kontrol Aliran Pasif, Splitter Plate Ganda, Silinder Sirkular, Karakteristik Wake, Drag Reduction, Passive Flow Control, Dual Splitter Plates, Circular Cylinder, Wake Characteristics |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ935 Pipe--Fluid dynamics. Tubes--Fluid dynamics |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Muhammad Ikhsan Khairul Afif |
| Date Deposited: | 30 Jul 2026 02:16 |
| Last Modified: | 30 Jul 2026 02:16 |
| URI: | http://repository.its.ac.id/id/eprint/140002 |
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