STUDI EKSPERIMENTAL PENGARUH JARAK ANTAR SILINDER DENGAN HELICAL RODS BER-GAP UNTUK KONFIGURASI TANDEM TERHADAP POLA ALIRAN DAN GAYA EKSITASI VORTEX SHEDDING

DWIPAYANA, KRESNA HADI (2017) STUDI EKSPERIMENTAL PENGARUH JARAK ANTAR SILINDER DENGAN HELICAL RODS BER-GAP UNTUK KONFIGURASI TANDEM TERHADAP POLA ALIRAN DAN GAYA EKSITASI VORTEX SHEDDING. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini berisi laporan eksperimen laboratorium untuk memeriksa pengaruh jarak antar dua silinder yang dilengkapi triple helical rods ber-gap terhadap gaya eksitasi dan pola aliran di belakang struktur tersebut. Dimensi triple helical rods ber-gap menggunakan dimensi efisien menurut Sugiwanto (2013). Eksperimen ini dilakukan di Laboratorium Low Speed Wind Tunnel, BBTA3 - BPPT, Serpong, Tangerang Selatan. Hasilnya adalah CD rata - rata dan CD rms silinder depan akan menurun seiring dengan bertambahnya jarak antar silinder (l/D). CD rata -rata dan CD rms silinder belakang mendapat efek shielding berturut – turut untuk CD rata - rata konfigurasi 1,75D; 3D dan 5D pada Re 4,2 x 10^4 sebesar 0,064; 0,213; 0,504 dan CD rms konfigurasi 1,75D; 3D dan 5D sebesar 0,138; 0,265; 0,599. Tidak terjadi perubahan signifikan akibat interferensi antar silinder terhadap CL rata - rata. Akan tetapi CL rms mendapat pengaruh interferensi signifikan pada jarak 1,75D di seluruh angka Reynolds dan 5D pada beberapa angka Reynolds berupa kenaikan CL rms. Untuk analisis pola aliran fluida, jarak 1,75D masuk kedalam kategori W-T1, sedangkan jarak 3D dan 5D masuk kedalam kategori W-T2 menurut klasifikasi Zdravkovich (1987) dan suppression device berperan dalam memecah vortex shedding yang terjadi. ==================================================================================================== This study contains reports of laboratory experiments to examine the effect of distance between the two cylinders attached by triple helical rods with air-gap to excitation forces and the flow pattern. Dimensions of the model according to (Sugiwanto, 2013). This experiment was conducted at the Laboratory of Low Speed Wind Tunnel, BBTA3 - BPPT, Serpong, South Tangerang. The result are CD mean and CD rms of the front cylinder decreases with increasing the distance between cylinder (l/D). CD mean and CD rms of rear silinder got shielding effects, respectively for CD mean of configuration 1,75D; 3D and 5D on Re 4,2 x 10^4 are about 0,064; 0.213; 0.504 and CD rms are about 0,138; 0,265; 0.599. No significant changes due to interference between the cylinder of the CL mean. However CL rms got a significant interference as shifting of CL rms on the distance 1,75D at whole Reynolds number and on the distance 5D at a few small Reynolds number. For the flow patterns, distance 1,75D classified into W-T1 while the distance of 3D and 5D classified into W-T2 according to the classification of Zdravkovich (1987) and the suppression device plays a role in breaking the vortex shedding.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Vortex Shedding, Koefisien Drag, Koefisien Lift, Pola Aliran, Suppression Device, Shielding Effect
Subjects: T Technology > TC Hydraulic engineering. Ocean engineering
T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures--Models
Divisions: Faculty of Marine Technology > Ocean Engineering > (S1) Undergraduate Theses
Depositing User: KRESNA HADI DWIPAYANA
Date Deposited: 25 Jan 2017 06:05
Last Modified: 25 Jan 2017 06:05
URI: http://repository.its.ac.id/id/eprint/3117

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