Sloshing Simulation of Three Types Tank Ship on Pitching and Heaving Motion

as an important part of a ship, tanker / cargo hold specifically designed to distribute the load to be maintained safely. In a related IMO classification of LNG carrier, there are a wide variety of types of LNG tanks on ships. Are generally divided into two types, namely tank (Independent Self Supporting Tank) and (Non Self Supporting Tanks). The tank-type variation will affect the characteristics of fluid motion that is inside the tank. Need for simulation of sloshing and analysis of the structure of the tank due to the force created by the load when the heaving and pitching. Sloshing the effect of the free movement of the fluid in the tank with the striking motion wall tank walls that can damage the walls of the tank. Type 1 tank is a tank octagonal (octogonal) for membrane-type LNG carrier with dimensions of length 38 m width 39.17 m 14.5 m high side of the tank. Type 2 tank is a tank-shaped capsule with the long dimension of 26.6 m and a diameter of 10.5 m. Type 3 tank is rectangular tank (rectanguler) with dimensions of length of 49.68 m, width 46.92 and 32.23 m high. Simulations conducted using Computational Fluid Dynamic (CFD) using ANSYS FLUENT software. From the simulation results concluded that the tank 1 to form (octogonal) have a total pressure of 3013.99 Pa on the front wall with a height of 13.65 m from the base of the tank Keywords fluent, heaving, pitching, sloshing, tank ship


I. INTRODUCTION 1
Tank is an important part of the central portion of the vessel for transporting liquids or gases.Therefore designed a ship fluid carrier (oil tanker) and LNG carrier ships in a certain size to transport the fluid that loads can be distributed safely.
According to the relevant IMO on the LNG carrier, there are a wide variety of types of LNG tanks on ships.Are generally divided into two types of tanks that standalone tank is not integrated with the ship's construction (Independent Self Supporting Tank) and the tank are not stand-alone and integrated with the ship's construction (Non Self Supporting Tanks).The tank-type variation will affect the characteristics of fluid motion that is inside the tank [1].
As the main storage medium, the tank will always get a load of fluid taken and expenses that come from outside the tank.Sloshing is one burden that comes from inside the tank and sea waves is the burden that comes from outside the tank in which both the load can result in damage to the tank wall [9].Hence the need for the simulation of sloshing and analysis of the structure of the tank due to the force created by the load.Sloshing the effect of the free movement of the fluid in the tank with the striking motion wall tank walls that can damage the walls of the tank [2].
In this research takes three types of LNG tanks with different shapes.The first tank is a tank type selfsupporting tank commonly called Self-supporting prismatic shape IMO type B (SPB tank).These tanks are designed to follow the shape of the hull (hull shape) that have a shape like a cube and discount simple Edi Djatmiko, Department of Marine Engineering, Sepuluh Nopember Institute of Technology, Surabaya, 60111, Indonesia.Email: gusjadmiko@gmail.comYoga Adhi Pratama, Department of Marine Engineering, Sepuluh Nopember Institute of Technology, Surabaya, 60111, Indonesia.Email: yogaadhi2704@gmail.comconstruction similar to the construction of the tank tanker.The second is the type of tank bilobe type (Shaped like capsules) are installed separately (independent) of the hull and supported (supported) with steel cylinder (skirt).And the third is the type of membrane tank.Visually, this tank has a octogonal shape) and is a non-self-supporting tanks or tanks do not stand alone [3,4].
Therefore, this study will analyze the characteristics of sloshing movement and direction of movement associated with the sloshing motion of the boat [10].With the sloshing analysis showed that the walls of the tank which parts are experiencing the greatest potential damage when the pitching and heaving [5,6].

A. Problem Formulation
Having regard to the subject matter that is contained in the background, then taken some formulation of the problem as follows: 1.How does the pitching and heaving motions against rectanguler shaped tank types, capsules and octogonal?2. How is the pressure / force which occurs in three variations of the design of the tank with filling level 50%? 3. How do the characteristics of fluid motion that is on the fluid in the tank three types?

B. Objectives Thesis
Based on the above background, the purpose and objective of this thesis is: 1. Modeling of three various types of tanks in CAD (Computational Adided Design) and CFD (Computational Fluid Dynamics) 2. Simulate sloshing against the three various types of filling the tank at the same level.From the simulation results there are differences in fluid motions in the three tanks.Seen from the chart below the total pressure and velocity that occurs in the first tank walls are as follows: The simulation results by the time calculation for 3000 time steps to show how the movement of the fluid and the total pressure on the walls of the tank as follows The front wall at z3 (13.65 m from the tank bottom) shows the total pressure at a maximum of 3013.99 kPa and a total pressure by an average of 1216.47 kPa, on z4 (9:10 am from the tank bottom) shows the total amounting to 21685.34 kPa maximum pressure and total pressure by an average of 19456.92kPa.
The rear wall of the z8 (13.65 m from the tank bottom) shows the total pressure up to 920.49 kPa and the total pressure by an average of 24.83 kPa, the z9 (9:10 am from the tank bottom) shows the total pressure at a maximum of 19084.64 kPa and total pressure by an average of 17123.30kPa.
From the graph it can be seen the movement of pressure on the front and rear walls average does not look stable pressure increase and decrease suddenly.The simulation results by the time calculation for 3000 time steps to show how the movement of the fluid and the total pressure on the walls of the tank as follows The front wall at z3 (13.65 m from the tank bottom) shows the total pressure at a maximum of 3013.99 kPa and a total pressure by an average of 1216.47 kPa, on z4 (9:10 am from the tank bottom) shows the total amounting to 21685.34 kPa maximum pressure and total pressure by an average of 19456.92kPa.
The rear wall of the z8 (13.65 m from the tank bottom) shows the total pressure up to 920.49 kPa and the total pressure by an average of 24.83 kPa, the z9 (9:10 am from the tank bottom) shows the total pressure at a maximum of 19084.64 kPa and total pressure by an average of 17123.30kPa.
To show the velocity in the tank wall is the front wall at z3 (13.65 m from the tank bottom) shows a maximum speed of 0439 m / s, the Z4 (9:10 am from the tank bottom) shows a maximum speed of 0439 m / s.
The rear wall of the z8 (13.65 m from the tank bottom) shows the maximum speed of 0.438 m / s, the z9 (9:10 am from the tank bottom) shows a maximum speed of 0439 m / s.
From the graph it can be seen the movement of the fluid and the total pressure and the front and rear walls average does not look stable pressure increase and decrease suddenly.From the simulation results seen from the graph below generate total pressure and velocity that occurs in the first tank walls are as follows:    Data simulation with a time calculation 3000 time step to show the total pressure on the walls of the tank 2 is on the front wall at z3 (5:24 am from the tank bottom) shows the total pressure at a maximum of 5259,714 kPa, on z4 (3:49 am from the tank bottom) shows the total pressure maximum amounting to 11790.46 kPa.The rear wall of the z8 (5:24 am from the tank bottom) shows a total of 4185.66 kPa maximum pressure, the z9 (3:49 am from the tank bottom) shows the total maximum pressure of 10587.99 kPa.In the graph velocity showed the front wall of the z3  Data simulation with a time step calculations for 3000 show the total pressure on the walls of the tank are as follows.The front wall at z3 (16:11 m from the tank bottom) shows the total pressure at a maximum of 12585.41kPa and total pressure by an average of 1646.39 kPa, on z4 (10.74 m from the tank bottom) shows the total pressure at a maximum of 32434.84kPa and total pressure average -average amounting to 22045.27kPa, The rear wall of the z8 (16:11 m from the tank bottom) shows the total pressure up to 9556.34 kPa and a total pressure by an average of 486.13 kPa, the z9 (10.74 m from the tank bottom) shows the total pressure at a maximum of 28897.48kPa and total pressure by an average of 19453.37 kPa.
In the graph indicates pressure constant motion but an increase in pressure on the front wall and rear wall of the tank, the longer it is used to calculate the greater the pressure given on the tank wall.Simulation data to show the velocity on the walls of the tank as follows: The front wall at z3 (16:11 m from the tank bottom) shows a maximum speed of 0.475 / s, the Z5 (5:37 am from the tank bottom) shows the total pressure at a maximum of 0480 m / s.
The rear wall of the z8 (16:11 m from the tank bottom) shows the maximum speed of 0.475 m / s, the z10 (5:37 am from the tank bottom) shows the total pressure at a maximum of 0.482 m / s

A. Conclusion
From the analysis of the three variations of the model octogonal shaped tank (membrane type) (a), capsule-shaped tank (type bilobe) (b) and rectangular shaped tank (type SPB) (c) and the above discussion to answer the purpose of this thesis can be summarized: discount total pressure on the front wall is greater than the total pressure on the rear wall seen from a maximum total pressure is given on the second wall tersebut.danif observed from the graph, the simulation results seem to occur increased pressure.The movement of the fluid in the tank has a constant maximum speed that does not happen enhancement and reduction in speed is soaring.3. Type 3 tank with rectanguler form (Type SPB) has the total pressure on the front wall is greater than the total pressure in the rear wall seen from the simulation results in the tank.Observed from the graph the total pressure applied to the wall it will increase pressure on the wall.The longer the calculation time is given, the total pressure will further increase.For speed of the fluid in the tank discount constant speed by an average of 0.3 m / s

B. Suggestion
Based on the analysis that has been done and could be concluded in writing, then it is given the following advice:

Figure. 16 .
Figure.16.Contour velocity magnitude on the tank 2 (5:23 am on the bottom of the tank) a maximum speed of 0439 m / s, the Z4 (3:49 am from the tank bottom) shows a maximum speed of 0439 m / s The rear wall of the z8 (5:23 am from basic tank) shows a maximum speed of 0.438 m / s, the z9 (3:49 am from the tank bottom) shows the total pressure at a maximum of 0439 m / s. C. Simulation Results Tank 3 Type SPB  Characteristics of Fluid Movement On Tank 1 From the simulation results seen from the graph below generate total pressure and velocity that Occurs in the first tank walls are as follows:

Figure 17 .
Figure 17.Contour of volume fraction

TABLE 5 CALCULATION
OF HYDROSTATIC

TABLE 7 .
NODE PRESSURE POTITION IN TANK 2 B. Simulation Results Tank 1 Type membrane  Characteristics of Fluid Movement On Tank 1

TABLE 9 .
THE TOTAL VALUE OF THE MAXIMUM PRESSURE IN THE TANK 2 Figure. 13.Contour velocity magnitude on the walls of the tank 2

TABLE 10 .
VALUE VELOCITY MAXIMUM MAGNITUDE AT FRONT AND REAR WALLS

TABLE 11 .
THE TOTAL VALUE OF THE MAXIMUM PRESSURE ON THE FRONT AND REAR WALLS

TABLE 14 .
VALUE MAXIMAL VELOCITY MAGNITUDE AT FRONT AND REAR WALLS (3)ernational Journal of Marine Engineering Innovation and Research, Vol.1(3),Jun.2017.175-188(pISSN: 2541-5972, eISSN: 2548-1479)188 1. Keep the variation filling the tank level and the location of other nodes to get more specific results 2. Need for comparison, variations and additions other than heaving and pitching motion so that fluid movement may be more in line with actual ship movements 3. Need for a comparative analysis between the experimental results and an analysis software to make more accurate 4. Keep the volume ratio equal to each tank