ANALISA GAYA DAN MOMEN HANYUT TERMINAL APUNG YANG RAMAH LINGKUNGAN DI PESISIR JAMBI

When a structure is floating in waves environment, a mean drift force in addition to the oscillatory hydrodynamic forces on the structure will occur. The reason of the occurrence of the drifting forces is that the waves transport the momentum horizontally and the structure will experience a mean horizontal reaction forces. Based on the model experiment, this paper evaluates the measurement results of a mean drift force and moment on the oil condensate tanker storage terminal in proximity in oblique waves (=90, 135, 180 Deg) environment of province Jambi. The model experiments were carried out in shallow basin of Indonesian Hydrodynamic Laboratory. Kata Kunci : Moment Hanyut, Oblique wave, Pesisir (Perairan Dangkal)

A simple fuzzy logic diagnosis system for control of internal combustion engines

Fuzzy logic (FL) systems are widely established as a technology offering an alternative system to tackle compound and ill defined problems. They can be trained from examples, are fault tolerant in the sense that they are capable to grip noisy and deficient data, are able to deal with non-linear problems, and once trained can perform prediction and generalization at high speed. in this paper a simple fuzzy logic control has been developed which is used for defining engine system faults and control and maintain them in a normal range without use any complicated mathematical equation and any fault sensor

Aerodynamic behavior of a compound wing configuration in ground effect

The aerodynamic coefficients of wing in ground effect can be affected with its design which can be the main parameter for efficiency of wing-in-ground effect craft. In this study, the aerodynamic coefficients of a compound wing were numerically determined in ground effect. The compound wing was divided into three parts with one rectangular wing in the middle and two reverse taper wings with an anhedral angle at the sides. An NACA6409 airfoil was employed as a section of wings. Three dimensional (3D) computational fluid dynamics (CFD) was applied as a numerical scheme. A realizable k-e turbulent model was used for simulation the turbulent flow around the wing surfaces. For validation purpose, the numerical results of a compound wing with aspect ratio 1.25, at ground clearance of 0.15 and different angles of attack were compared with the current experimental data. Then, the aerodynamic coefficients of the compound wings were computed at various ground clearances and angle of attack of 4°. According to pressure and velocity distribution of air around wing surfaces, ground clearance had considerable effects on ram effect pressure and tip vortex of the compound wing, and aerodynamic coefficients of the compound wing had some improvements as compared with the rectangular wing

Static stability of a compound wing configuration in ground effect

The height static stability of a wing can be a main concern for conceptual design of wing-in-ground effect (WIG) crafts. In this research, the stability of a rectangular and compound wing was computationally predicted in ground effect. A realizable k-e turbulent model was used for simulation the flow filed over the wing surfaces. First, the drag coefficient and lift to drag ratio of numerical simulation were validated by experimental data of the rectangular wing. Next, the stability of the compound wing respect to different ground clearances will be determined and compared with rectangular wing. This study illustrated a deep understanding of static stability of present compound wing in ground effect, which eventually can be a guideline for researchers and designers of WIG craft

Super yatch design study for Malaysian sea (Langkawi Island)

Malaysia as a country surrounded by water has a huge economic and geographical potential in the development of super yacht industry in South East Asia. There is lack of super yacht design study specifying to Malaysian marinas and seas. Most of the super yacht operates in Malaysia were built and bought directly from oversea, and chartered by foreign companies. It is hence the purpose of this study to survey on Malaysian sea water, particularly Langkawi Island, to introduce a design methodology in producing a preliminary design of super yacht that suits Langkawi Island, and serves as a guideline for future super yacht design for Malaysian sea in different marinas. Suitable dimensions of super yacht were derived by using dimensional relationship via statistical method. Two types of hull form designs (round bilge and V-bottom hull) were designed using Maxsurf Pro software. Resistance analysis on the two hull forms were carried out using Savitsky Pre-Planing and Compton methods via MaxsurfHullspeed software, and stability performance of the two hull forms was analyze using Hydromax software. VBottom hull form is found to have better resistance performance as compared to round bilge hull form, and both hull forms are found to be in stable conditions and comply with IMO requirements

Surge forces of a FPSO at lee side of submerged plate in regular waves

A submerged horizontal plate type breakwater is not only to be good energy dissipates of wave breaking on the top of the plate, but also to generate steady flow and to reproduce shorter waves. This paper assessed a submerged plate which is applied to set up for an Oil/Gas Floating Production Storage and Offloading (FPSO) structure. The wave exciting surge forces of the FPSO at the lee side of the submerged plate were examined by using Boundary Element Method based on the potential theory. In order to verify the numerical results, the model experiments have been carried out in Towing Tank of Laboratorium Hidrodinamika Indonesia, BPP Teknologi. By comparing the numerical results with the experimental ones, the results show that the numerical results have similar tendency to the experimental ones, and it is deduced that the submerged plate reduces effectively the wave exciting surge forces at low wave frequencies

Analysis of motion on FPSO in shallow water with a non-collinear environment

The ship-shaped floating structures like FPSO has an ability to produce, storage and offloading the oil but it is does not have the drilling capability. Usually the FPSO in shallow water is connected with the single point mooring systems such as Vertical Anchor Leg Mooring (VALM) buoy systems. The objective of this paper is calculate the response amplitude operators (RAO) of spread moored FPSO with two mooring configuration and with the effect of non-collinear environment of wave and current. The analyses done by using ANSYS AQWA (version 14) software with runs two types of analysis which is hydrodynamics diffraction and hydrodynamics time response. The analysis also focuses to calculate the RAO and normalized hawser line force of FPSO and VALM systems. The result from the software has been compared with the experiment result to validate it. The different in meshing elements size also are taken into account. The analysis also focuses to compare the RAO between single leg mooring FPSO and spread moored FPSO with the same loading condition. From the analysis, the RAO for 4 mooring FPSO is higher compared than 8 mooring FPSO but the 8 mooring FPSO shows high value of cable forces than 4 mooring FPSO. It also shows the value of RAO of single leg mooring FPSO is higher compared to the spread moored FPSO

Numerical structural analysis on a composite main wing of wig craft

This paper presents a finite element model for structural analysis of composite main wing for an oneseater Wing in Ground Effect (WIG) craft. FEA models have been developed using sandwich construction having composite skin - spar laminates and foam core. The analysis for main wing structure through numerical structural analysis are developed using commercial FEM code ABAQUS. Displacement boundary conditions are employed for the global model. A critical area with high displacement and stress is developed with global mesh. Materials failure criteria for composites are applied on the model and failure index is checke

Effects of coastal development on ship manoeuvring and navigation

Coastal development, such as land reclamation or dredging, usually changes the characteristics of the coastal waterway. A common phenomena due to restricted waterway is increase in ship resistance and reduction in manoeuvrability. The restricted water inflow under the vessel, result in increased water velocity under the hull. The increase of the inflow velocity at the rudder may result in the increase of the rudder normal force or create partial vacuum in the region near propeller and rudder. Consequently, manoeuvring of ships may become erratic in this condition. Standard for ship maneuvrabiity have been developed by International Maritime Organization (IMO) to ensure safe navigation/ship handling operation of ships. The standards provide criteria on the ship turning ability, yaw checking ability, course keeping ability and stopping ability. Where there is uncertainty in the behavior of the vessel especially in restricted waters, the use of numerical simulation for evaluating navigational risks is highly depended upon. In this paper, firstly, the effects on water depths and currents due to coastal development will be described. Secondly, using time domain simulation approach, the manoeuvring characteristics of vessel in two scenarios, i.e. deep and shallow water are discussed. Thirdly, actual simulations demonstrating the risks involved in navigating in a restricted waterway will be demonstrate