Analisa Hambatan Kapal Akibat Kekasaran Tak-Homogen Di Arah Melintang Dengan Metode CFD: Studi Kasus KRISO Container Ship

Ganfi, Muhammad Ridho Fauzan (2022) Analisa Hambatan Kapal Akibat Kekasaran Tak-Homogen Di Arah Melintang Dengan Metode CFD: Studi Kasus KRISO Container Ship. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

[img] Text
04111740000054_Undergraduate_Thesis.pdf - Accepted Version
Restricted to Repository staff only until 1 April 2024.

Download (4MB) | Request a copy

Abstract

Biofouling akan muncul pada lambung kapal setelah kapal setelah beroperasi dalam jangka waktu tertentu. Biofouling ini akan meningkatkan kekasaran lambung kapal yang pada akhirnya dapat meningkatkan hambatan kapal. Sudah banyak penelitian yang mempelajari efek kekasaran terhadap kapal yang dimana kekasaran dimodelkan dalam bentuk homogen. Namun kekasaran dapat juga ditemukan memiliki bentuk tak-homogen. Scraping fouling yang tidak merata dapat menghasilkan kekasaran tak-homogen dalam bentuk strip-strip horizontal pada permukaan lambung kapal. Penelitian ini bertujuan untuk menganalisis dampak kekasaran tak-homogen yang berupa strip-strip memanjang pada permukaan kapal terhadap koefisien hambatan gesek (CF) dan koefisien hambatan total (CT) kapal dengan menggunakan metode CFD. Strip-strip memanjang ini akan membentuk arus sekunder yang memiliki arah melintang terhadap kapal yang diakibatkan oleh arah arus fluida yang mengalir dari haluan kapal. Setiap strip kekasaran ini memiliki tinggi kekasaran ks = 325.00 μm dan memiliki lebar (l) sebesar 50 cm. Model strip kekasaran tak-homogen ini divariasikan menjadi tiga berdasarkan jarak antar-stripnya yaitu 250 cm, 500 cm dan 750 cm. Selain simulasi dengan kekasaran tak-homogen, juga dilakukan simulasi dengan permukaan halus (ks = 0 μm) dan dengan permukaan dengan kekasaran homogen (ks = 325.00 μm). Penelitian ini menggunakan KRISO Container Ship sebagai model kapal dan simulasi CFD dilakukan dalam kondisi full viscous dan free surface. Hasil simulasi CFD berupa hambatan gesek (RF) dan hambatan total (RT) yang akan diubah menjadi nilai koefisien hambatanya untuk dibandingkan. Hasil penelitian menunjukan bahwa kekasaran permukaan meningkatkan koefisien hambatan gesek kapal. Variasi lambung dengan kekasaran homogen menyebabkan peningkatan CF terbesar yaitu sebesar 54.18% dari lambung halus, sementara variasi lambung dengan kekasaran tak-homogen dengan jarak strip terbesar memiliki peningkatan nilai CF terkecil yaitu sebesar 5.24% dari lambung halus. Sehingga dapat disimpulkan bahwa jarak antar-strip mempengaruhi koefisien hambatan gesek, semakin lebar jarak antar-strip maka akan semakin rendah peningkatan hambatan gesek pada kapal. Pada variasi kekasaran tak-homogen lateral juga didapatkan penebalan boundary layer akibat kekasaran permukaan yang signifikan hanya terjadi pada permukaan yang memiliki strip kekasaran. ================================================================================================ Biofouling will appear on the hull of the ship, after the ship has operated on a certain period of time. Biofouling produces roughness in the surface of the hull which increases the resistance of the ship. There have been many studies about the effects of surface roughness on ships where roughness is modeled in a homogeneous form. However, roughness can also be found in an inhomogeneous form. Uneven scraping of fouling can cause inhomogeneous roughness in the form of horizontal strips in the hull of the ship. This study aims to analyze the effects of inhomogeneous roughness in the form of longitudinal strips on the surface of the ship towards the ship’s friction resistance coefficient and total resistance coefficient using CFD method. The longitudinal strip will form a secondary current that has a transverse direction to the ship caused by the direction of the fluid current flowing from the bow to the stern of the ship. Each of these strips has a roughness height of ks = 325.00 μm and widht (l) of 50 cm . The strips model will be varied into three variation based on the distance between the strips, namely 250 cm, 500 cm and 750 cm. In addition of simulation with inhomogeneous roughness, this study will also conduct simulations on a smooth hull surface (ks = 0 μm) and also a hull surface with homogeneous roughness (ks = 325.00 μm). This study uses KRISO Container Ship as a model and the CFD simulation will be conducted in full viscous and free surface conditions. The results of the CFD simulation are friction resistance (RF) and total resistance (RT) which will be converted into resitance coefficient form for comparison. The results of this study showed that surface roughness incresases the friction resistance coefficient of the ship. The variation of hull with a homogeneous roughness caused the largest increase in CF value which is 54.18% increase from smooth hull surface, while the variation og hull with inhomogeneous roughness with the largest distance distance between the strips had the smallest increase in CF value which is 5.24% increase from smooth hull surface. So it can be concluded that the distance between the strips affects the ship’s friction resistance coefficient,, the wider the distance of the strips, the lower the increase in the ship’s friction resistance. It is also observed that the increase in the boundary layer thickness of the variation with an inhomogenous roughness in the spanwise direction only occurs significantly on the surfaces that have a roughness strips

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: CFD, hambatan gesek, hambatan total, kekasaran, kekasaran homogen, kekasaran permukaan, kekasaran tak-homogen di arah melintang. ============================================================= CFD, friction resistance, total resistance, homogeneous roughness roughness, inhomogeneous roughness in the spanwise direction, surface roughness.
Subjects: V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering
V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM156 Naval architecture
V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM161 Ships--Hydrodynamics
V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM751 Resistance and propulsion of ships
Divisions: Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User: Muhammad Ridho Fauzan Ganfi
Date Deposited: 11 Feb 2022 03:34
Last Modified: 11 Feb 2022 03:34
URI: https://repository.its.ac.id/id/eprint/93754

Actions (login required)

View Item View Item