Pemodelan Numerik Dua-Fase Eulerian untuk Gerusan dan Resedimentasi Pipa Dasar Laut akibat Variasi Kecepatan Gelombang dan Arus pada Kondisi Monsun Tropis

Fabiola, Aurellia Amanda (2026) Pemodelan Numerik Dua-Fase Eulerian untuk Gerusan dan Resedimentasi Pipa Dasar Laut akibat Variasi Kecepatan Gelombang dan Arus pada Kondisi Monsun Tropis. Other thesis, Institut Teknologi Sepuluh Nopember.

Text 5020221008-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (10MB) | Request a copy

Abstract

Free span pada pipa bawah laut dapat meningkatkan risiko kegagalan struktural, dan salah satu penyebab utamanya adalah gerusan (scour) yang menggerus tumpuan sedimen di bawah pipa. Namun, lubang gerusan ini tidak selalu bertambah dalam terus-menerus, melainkan dapat terisi kembali melalui proses pengisian kembali (backfilling) ketika kondisi gelombang-arus berubah mengikuti musim. Penelitian ini memodelkan dinamika scouring-resedimentasi pada pipa bawah laut menggunakan solver dua-fase Eulerian SedFoam berbasis OpenFOAM, untuk kondisi Monsun Barat (S1, KC = 51) dan Monsun Timur (S2, KC = 13,4) di segmen Zona 17 jalur pipa SSWJ, Laut Jawa, dengan tiga variasi ukuran butir sedimen (d50 = 0,26; 0,36; dan 0,50 mm), dilanjutkan dua skenario backfill (BF-S1 dan BF-S2) yang mewakili kondisi setelah forcing monsun melemah. Model divalidasi terhadap data eksperimen Dhamelia et al. (2025) dengan MAPE sebesar 4,44%, jauh di bawah batas penerimaan 10%. Hasil simulasi menunjukkan kedalaman gerusan equilibrium (Seq/D) pada S1 selalu lebih besar daripada S2, dengan nilai tertinggi 0,530 dan terendah 0,360, sementara skala waktu gerusan tak berdimensi (T*) relatif stabil di angka 35 pada kedua skenario dan tidak terlalu terpengaruh oleh perubahan d50. Pada tahap backfill, BF-S2 menghasilkan rasio resedimentasi (R) yang jauh lebih tinggi, sampai 0,767, dibanding BF-S1 yang hanya 0,324, meski proses backfill pada BF-S2 justru berlangsung lebih lambat, sejalan dengan temuan bahwa skala waktu backfilling bisa satu orde magnitudo lebih besar dibanding skala waktu gerusan.
===============================================================================================================================
Free spans in subsea pipelines can raise the risk of structural failure, and one of the main causes is scour, which erodes the sediment supporting the pipe. A scour hole does not always keep deepening, however, and can be filled back in through backfilling as wave-current conditions shift with the seasons. This study models scour-resedimentation dynamics around a subsea pipeline using the two-phase Eulerian solver SedFoam built on OpenFOAM, under West Monsoon (S1, KC = 51) and East Monsoon (S2, KC = 13.4) conditions at Zone 17 along the SSWJ pipeline corridor, Java Sea, with three sediment grain sizes (d50 = 0.26, 0.36, and 0.50 mm), followed by two backfill scenarios (BF-S1 and BF-S2) representing conditions after the monsoon forcing weakens. The model was validated against the experimental data of Dhamelia et al. (2025) with a MAPE of 4.44%, well below the 10% threshold. Results show equilibrium scour depth (Seq/D) for S1 always higher than S2, peaking at 0.530 and dropping to 0.360, while the dimensionless scour timescale (T*) stays close to 35 for both scenarios regardless of grain size. During backfilling, BF-S2 produces a much higher resedimentation ratio (R), up to 0.767, compared to only 0.324 for BF-S1, even though backfilling under BF-S2 takes longer, consistent with prior findings that backfilling timescales can run an order of magnitude longer than scour timescales.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	pipa bawah laut, gerusan (scour), backfilling, sedFoam, monsun tropis. subsea pipeline, scour, backfilling, sedFoam, tropical monsoon,
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Aurellia Amanda Fabiola
Date Deposited:	29 Jul 2026 06:32
Last Modified:	29 Jul 2026 06:32
URI:	http://repository.its.ac.id/id/eprint/139497

Actions (login required)

View Item