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The demand for liquid carriers, such as liquefied natural gas (LNG), has increased in recent years. One of the most common types of LNG carriers is the membrane type, which is often built by a shipyard with a prismatic tank shape. This carrier is commonly known for its effective ways to mitigate sloshing using a baffle. Therefore, this study was performed to evaluate sloshing in a prismatic tank using vertical and T-shape baffles. The sloshing was conducted with 25% and 50% filling ratios because it deals with the nonlinear free-surface flow. Furthermore, the smoothed particle hydrodynamics (SPH) was used to overcome sloshing with ratio of a baffle and water depth is 0.9. A comparison was made for the dynamic pressure with the experiment. The results show that SPH has an acceptable accuracy for dynamic and hydrostatic pressures. Baffle installation significantly decreases the wave height, dynamic pressure and hydrodynamic force.

Parametric geometric modeling plays an important role in ship's hull form optimization by use of computational fluid dynamic (CFD) analysis. However, it is difficult to create satisfactory parametric modeling for some curved shapes, such as a ship's bulbous bow. In this study, the cubic Bezier curve and curve-plane intersection methods are applied to generate the parametric design of a bulbous bow in a solid modeling procedure by taking into account the input of 4 (four) design parameters. For this, a suitable application program interface script within the ANSYS Design Modeler was developed. An application to the ship resistance minimization by use of CFD was made to show that the proposed method could be implemented properly. In this respect, the parametric design of the bulbous bow of a container ship (KRISO Container Ship type) was chosen to be modified. First, it was shown that the computational results generated by CFD were close to the experimental data for the original ship hull form. The developed optimization method was subsequently applied to find the optimal bulbous bow. Finally, the dependence of the optimum bulbous bow on a ship's speed (some variations of Fn values) was investigated and the results were compared to each other.

Sloshing is one of challenging problem in the free surface flow, because is dealing with large deformation of fluid. The present paper was carried out of numerical sloshing in the prismatic tank that resemble of LNG membrane type carrier. Pressure sensor was used to validate the dynamic pressure in low filling ratio of tank. Forced oscillation motion in sway with f = 1.08 Hz and amplitude of motion 6.52 mm. A single, and double vertical baffles are used to reduce dynamic pressure and hydrodynamic force. The ratio of baffle heigh with water depth is 0.9. A meshless computational fluid dynamics (CFD) was used to reproduce sloshing in the prismatic tank. Smoothed particle hydrodynamics (SPH) is one of the major meshless CFD. In addition, The advanced visualization was performed using Blender version 2.92. The results showed the vertical baffles effectively reduce the dynamic pressure and hydrodynamic force. Moreover, the advanced visualisation made sloshing simulation more realistic, and attracting compare conventional SPH post-processing.

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As a part of the important thing in ship design is propeller design. Propeller its self has many kinds of the design. This study investigates the effect on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the Computational Fluid Dynamics (CFD) method. These simulations were compared in accordance SHUSKIN nozzle that has 3 types of design. Each type of thruster model indicates different force and torque. Thus, for the analysis will be generated by each model and it can be discovered that which model has the most optimal for the thrust. The analysis by using CFD indicates the change of fluid flow around the ducted propeller. The results showed that the nozzle on the propeller will give the extra of thrust for the performance of propeller. IntroductionMany remote operated vehicle (ROV) have been developed for the maintenance and inspection of ocean structures. Most of them in practical use are self-propulsive with umbilical cable. To avoid the effects of noise force from the cable a free swim power would be ideal, but most are tethered, then the electrical power can be supplied and control signals and data obtained can be transmitted. A self-propulsive ROV can be guided to target more accurately than towed one. Consequently, a tethered self-propulsive which is usually used to inspect and maintain ocean structures [1]. In ship hydrodynamics, fixed propellers, also named screw propellers, have an important place among the propulsion systems to propel a ship. Propeller design is to obtain the optimum propeller which applies to minimum power requirements and against maximum efficiency conditions at an adequate revolution number. Usually two methods are used in the propeller design. The first is use diagrams obtained from the open water propeller experiments for systematic propeller series. The second is to use mathematical method (lifting line, lifting surface, vortex-lattice, boundary element method)

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