Putra, Fardiansyah Cahya Pratama (2015) Studi Karakteristik Vortex shedding dari Interaksi Hidrodinamika dengan Pemasangan Multiple helical rods ber-gap pada Sebuah Silinder Kaku. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Vortex shedding merupakan sebuah fenomena yang sering terjadi pada bagian
struktur bangunan lepas pantai yang berada didalam air. Beberapa contoh bagian
tersebut adalah jacket leg, riser, pipeline, conductor, dll. Pengaruh suppression
device sangat besar dalam menanggulangi besarnya gaya hidrodinamis yang
terjadi pada objek silinder yang terkena aliran fluida. Penelitian ini menggunakan
permodelan numeris melalui CFD (Computational Fluid Dynamic). Penambahan
helical rods ber-gap sebagai suppression device berpengaruh terhadap penurunan
CD (drag coefficient) dan CL (lift coefficient). Penurunan secara signifikan terjadi
pada konfigurasi pemasangan helical rods ber-gap pada arah datang aliran 0o,
pengurangan terjadi pada Cd sebesar ±3.5% (Re = 104) dan ±12% (Re = 105)
sedangkan pada CL terjadi pengurangan sebesar ±777% (Re = 103), ±142% (Re =
104) dan ±645% (Re = 105). Penambahan multiple helical rods ber-gap yang
berpengaruh terhadap penurunan CD dan CL adalah konfigurasi pemasangan
multiple helical rods dengan arah datang 0o, pengurangan terjadi pada CD sebesar
±4.5% (Re = 104) dan ±6% (Re = 105) sedangkan penurunan untuk nilai CL
sebesar ±218% (Re = 105). Pola aliran yang melewati silinder setelah
ditambahkan helical rods ber-gap dapat merusak vortex shedding yang terbentuk.
Didapatkan hasil bahwa frekuensi vortex shedding terjadi pada bare cylinder dan
silinder yang ditambahkan helical rods memiliki nilai yang sama, yakni 1Hz, hal
ini karena keterbatasan data sehingga tidak mendapatkan hasil yang detail
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Vortex shedding is a common phenomenon in the offshore part of the building
structure which has a cylindrical geometry, some examples of these parts is the
jacket leg, risers, pipelines, conductor, etc. Effect of suppression devices are very
large in magnitude overcome hydrodynamic force that occurs in the affected
cylinder object fluid flow. In this thesis research will be carried out by numerical
modeling by CFD (Computational Fluid Dynamics). The use of multiple helical
rods with gap with the direction variations can reduce CD (drag coefficient) and
CL (lift coefficient) but the decline is not too significant, even in some of the
Reynolds number increases, the incoming flow directions 0o, with a reduction of ±
4.5% at Re = 104 and ± 6% at Re = 105 for CD value and ± 218% at Re = 105 for
CL. This result is much more inefficient when compared to the triple helical rods,
which incoming flow direction 0o, with a reduction of ± 3.5% at Re = 104 and ±
12% at Re = 105 for CD and ± 777% at Re = 103, ± 142% at Re = 104 and ± 645%
at Re = 105 for CL. Flow pattern that occurs after passing through the cylinder,
gapped helical rods may damage the vortex shedding formed. Showed that the
frequency of vortex shedding occurs in bare cylinder and addition of helical rods
have the same value, 1Hz, this can be due to limitations of the data so it does not
get the results that detail
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | RTKe 627.98 Put s |
| Uncontrolled Keywords: | Vortex shedding , suppression devices, helical rods ber-gap, multiple helical rods ber-gap, variasi gap |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures |
| Divisions: | Faculty of Marine Technology (MARTECH) > Marine Engineering > 36101-(S2) Master Theses |
| Depositing User: | Mr. Tondo Indra Nyata |
| Date Deposited: | 03 Jul 2017 07:20 |
| Last Modified: | 24 Aug 2018 04:30 |
| URI: | http://repository.its.ac.id/id/eprint/41848 |
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