scholarly journals ANALISA KOMPONEN HAMBATAN KAPAL IKAN TRADISIONAL DI PERAIRAN CILACAP

2016 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
S Samuel
Keyword(s):  
Water Resistance ◽  
Frictional Resistance ◽  
Slender Body ◽  
Resistance Components ◽  
Fishing Boat ◽  
Calm Water ◽  
Double Hull ◽  
Traditional Fishing ◽  
Body Method ◽  
Resistance Component

<p><em>RESISTANCE COMPONENT ANALYSIS OF TRADITIONAL FISHING BOAT IN CILACAP</em></p><p><em><br /></em></p><p><em>Monohull fishing boats used to catch fish is modified into a catamaran boat. The purpose of this modification is to get more fish. Catamaran ship has a double hull, but with the double hull ships resulted in increasingly complex resistances. It is interesting to study in depth about the resistance components of Catamaran boat. Resistance Components not only consist of surge resistance, frictional resistance, and the form resistance but with the distance between demihull causing interference waves. There are many research results of Catamaran boat in that aspect, but the data and information obtained from the experiment is still inadequate. In addition, there is still lack of accuracy particularly in predicting interference resistance component in calm water (calm-water resistance) as a result of the distance between the demihull. This study aims to describe the resistance component at Catamaran boat by using slender body method.</em><strong><em></em></strong></p><p align="center"><strong> </strong></p><p><strong>Keywords</strong>: <em>catamaran, Cilacap, slender body method</em></p><p> </p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p><em>Kapal ikan monohull yang biasa digunakan untuk mencari ikan dimodifikasi menjadi kapal catamaran. Tujuan modifikasi ini untuk mendapatkan muatan ikan yang lebih banyak. Kapal Catamaran mempunyai dua lambung, tetapi dengan adanya dua lambung mengakibatkan hambatan kapal semakin kompleks. Menarik untuk dikaji lebih lanjut tentang komponen hambatan kapal Catamaran. Komponen hambatan tidak hanya terdiri dari hambatan gelombang, hambatan gesek, dan hambatan bentuk namun dengan adanya jarak antar demihull sehingga menimbulkan interferensi gelombang. Sudah banyak dijumpai hasil riset kapal Catamaran pada aspek tersebut, tetapi data dan informasi yang diperoleh dari eksperimen masih kurang memadai. Disamping itu, masih ditemukan ketidak-akurasian khususnya dalam memprediksi interferensi komponen hambatan pada air tenang (calm-water resistance) akibat dari adanya jarak antar demihull tersebut. Penelitian ini bertujuan untuk memaparkan komponen hambatan pada kapal Catamaran dengan menggunakan slender body method. </em></p><p> </p><p><strong>Kata kunci</strong>: <em>catamaran, Cilacap, slender body method</em></p>

Study of Prismatic Planing Model Spray and Resistance Components

1983 ◽  
Vol 27 (03) ◽  
pp. 187-196
Author(s):  
Robert Latorre
Keyword(s):  
Frictional Resistance ◽  
Total Resistance ◽  
Wide Beam ◽  
Resistance Components ◽  
Turbulent Transition ◽  
Measured Resistance ◽  
Pressure Resistance ◽  
Resistance Tests ◽  
Resistance Component ◽  
Good Agreement

The results of a study of prismatic planing model spray and resistance components are presented. The calculated total resistance values are shown to be in good agreement with the measured resistance. The features of the whisker spray and spray blister are discussed along with an experimental technique using wide-beam prismatic models for measuring the spray thickness. A derivation based on energy considerations of the prismatic planing hull pressure resistance component and the spray thickness is presented. The spray thickness values calculated from this formulation are in qualitative agreement with the measured spray thickness. The frictional resistance component obtained from the resistance measurements indicated an extensive laminar flow on the planing model bottom. An acetanilid film was sprayed on the planing model bottom which tripped the laminar-turbulent transition. The CF-values estimated from the acetanilid film pattern were found to be 75 to 90 percent of the CF-values estimated from the corresponding resistance tests.

Numerical and Experimental Analysis of Added Resistance of Ships in Waves

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Ould el Moctar ◽  
Sebastian Sigmund ◽  
Jens Ley ◽  
Thomas E. Schellin
Keyword(s):  
Water Resistance ◽  
Frictional Resistance ◽  
Medium Size ◽  
Total Resistance ◽  
Added Resistance ◽  
Short Waves ◽  
Radiation Forces ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Force Components

Two Reynolds-Averaged Navier–Stokes (RANS) based field methods numerically predicted added resistance in regular head waves for a 14,000 TEU containership and a medium size cruise ship. Long and short waves of different frequencies were considered. Added resistance was decomposed into diffraction and radiation force components, whereby diffraction forces were obtained by restraining the ship in waves and radiation forces by prescribing the motions of the ship in calm water. In short waves, the diffraction part of total resistance was dominant as almost no ship motions were induced. In long waves, the sum of diffraction and radiation forces exceeded total resistance, i.e., the interaction of these two force components, which caused the reduction of total resistance, needed to be accounted for. Predictions were compared with model test measurements. Particular emphasis was placed on the following aspects: discretization errors, frictional resistance as part of total added resistance in waves, and diffraction and radiation components of added resistance in waves. Investigations comprised two steps, namely, a preliminary simulation to determine calm water resistance and a second simulation to compute total resistance in waves, always using the same grids. Added resistance was obtained by subtracting calm water resistance from total averaged wave resistance. When frictional resistance dominated over calm water resistance, which holds for nearly all conventional ships at moderate Froude numbers, high grid densities were required in the neighborhood surrounding the hull as well as prism cells on top of the model's surface.

Numerical and Experimental Analysis of Added Resistance of Ships in Waves

2015 ◽  
Author(s):  
Ould el Moctar ◽  
Sebastian Sigmund ◽  
Thomas E. Schellin
Keyword(s):  
Water Resistance ◽  
Frictional Resistance ◽  
Medium Size ◽  
Total Resistance ◽  
Added Resistance ◽  
Short Waves ◽  
Radiation Forces ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Force Components

A RANS-based field method numerically predicted added resistance in regular head waves for a 14000 TEU containership (Duisburg Test Case) and a medium-size cruise ship. We concentrated our investigations on short waves. For different frequencies, we decomposed added resistance into diffraction and radiation force components, whereby diffraction forces were obtained by restraining the ship in waves and radiation forces, by prescribing the motions of the ship in calm water. In short waves, the diffraction part of total resistance was dominant as almost no ship motions were induced. In long waves, the sum of diffraction and radiation forces exceeded total resistance, i.e., the interaction of these two force components, which caused the reduction of total resistance, had to be accounted for. Predictions were compared with model test measurements. Particular emphasis was placed on the following aspects: discretization errors, frictional resistance as part of total added resistance in waves, diffraction and radiation components of added resistance in waves, and the influence of surge motion on added resistance. Investigations comprised two steps, namely, a preliminary simulation to determine calm-water resistance and a second simulation to compute total resistance in waves, always using the same grids. Added resistance was obtained by subtracting calm-water resistance from total averaged wave resistance. When frictional resistance dominated calm-water resistance, which holds for nearly all conventional ships at moderate Froude numbers, high grid densities were required in the neighborhood surrounding the hull.

scholarly journals PENGARUH POSISI CENTERBULB BERBENTUK FOIL TERHADAP KOMPONEN HAMBATAN KAPAL IKAN KATAMARAN MV. LAGANBAR

2020 ◽  
Vol 12 (1) ◽  
pp. 64-71
Author(s):  
Muhammad Iqbal ◽  
Parlindungan Manik ◽  
Eko Sasmito Hadi ◽  
Achmad Kurniawan
Keyword(s):  
Wave Resistance ◽  
Viscous Resistance ◽  
Ship Resistance ◽  
Resistance Components ◽  
Double Hull ◽  
Resistance Component

Catamarans are double hull ships which have many advantages over single hull ships with the same displacement. To increase catches, fishermen in Cilacap converted ships from the original single hull with outrigger to double hull (catamaran). Displacement of ships has doubled. But the ship's resistance increased to almost 4 times. To reduce the resistance of catamarans, some researchers use the concept of center bulb. In this study, the center bulb form used foil. The purpose of this study was to determine the effect of center bulb position on ship resistance components by comparing 9 center bulb positions. The results stated that of the nine center bulb position configurations, Model 6 is the best model because at Fr 0.35 it can reduce ship resistance by up to 33%. For the viscous resistance component it is not significantly affected by the use of the center bulb. But on the wave resistance component, the use of this center bulb can reduce wave resistance by 47% at Fr 0.35.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

Calm-Water Resistance

2018 ◽  
pp. 139-210
Author(s):  
Liang Yun ◽  
Alan Bliault ◽  
Huan Zong Rong
Keyword(s):  
Water Resistance ◽  
Calm Water

Comparison of Two Base-Potentials for a Slender-Body Method

2012 ◽  
Author(s):  
Mahmoud Alidadi ◽  
Sander Calisal
Keyword(s):  
Three Dimensional ◽  
Slender Body ◽  
Surface Boundary ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Wave Elevation ◽  
Surface Boundary Conditions ◽  
Perturbation Potential ◽  
Order Of Magnitude ◽  
Body Method

The effects of two base-potentials on the accuracy of a slender-body method are studied in this paper. In the formulation for this method which is developed for the slender ships, the velocity potential is decomposed into a base-potential and a perturbation potential. Then using an order of magnitude analysis, the three-dimensional flow problem is simplified into a series of two-dimensional problems for the perturbation potential. These two-dimensional problems are solved with the linearized free surface boundary conditions, using a mixed Eulerian-Lagrangian method. Finally for the two base-potentials, the numerical wave elevation along a Wigleyull are compared with the experimental results.

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