The problems in port infrastructures related with climate change, especially sea level rise, have continued to receive a high level of attention. Knowledge of climate change should become a major interest for engineer, stakeholders, and decision makers or the port authorities in port industry for developing mitigation and adaptation strategies in the future. The objective of this paper is to measure sea level change in the Indonesian sea from satellite altimetry. In this study, satellite altimetry mission of Jason-2 are used to obtain altimetry data from NOAA server databse. These data are processed by using software Basic Radar Altimetry Toolbox (BRAT). Analysis of sea level change is done for 4 years period from 2009 to 2012 in 4 locations, which are Medan, Pemangkat, Ambon, and Manokwari. The results showed that the highest sea level rise is in Manokwari 14.10 mm/year, and the lowest is in Ambon with trend of sea level rise 1.17 mm/year.
Department of Ocean Engineering, Faculty of Marine Technology, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
Operational Research Laboratory, Department of Ocean Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
This paper describes a new implementation of a vortex lattice method based on modified lifting line (VLML) for ship propeller-rudder. Method has been employed to estimate hydrodynamic performance and flow fields, for design and analysis. For this purpose, the results obtained using theoretical model are validated against experimental data, carried by Tamashima et al. [18], concerning to propulsor system. Comparison of these results indicates good agreement with those of the experimental data. Therefore the method can be used as a fast tool for preliminary design and analysis.
Department of Ocean Engineering, Amirkabir University of Technology (AUT), Iran
Numerical Study on the Fluid Forces of a Rigid Cylinder Covered by Helical Rods with Gap Due to the Variations of Incoming Flow Direction and Pitch at Reynolds Number 1000
Offshore structures such as a jacket platform, risers, conductors, mooring lines, Spars, and pipelines, are subject to severe vibration due to Vortex-induced vibration (VIV). This vibration can lead the structures to fatigue failure. One of a passive suppression device which effectively reduces the VIV is in the form of triple helical rods with gap covered to a cylinder. The present paper specially discusses the influence of incoming flow direction and pitch of helix on the induced fluid forces acting on the cylinder due to addition of helical rods at Reynolds number (Re) of 103. The configuration produced best reduction on drag and lift forces in CFD simulation are with 30D length of pitch for the incoming flow direction of 0° and 60°. Reduction on the drag and lift forces for incoming flow directions of 0° and 60° are respectively, 11.34% and 88.32%, and 10.99% and 97.94%.
Graduate Program on Marine Technology, Faculty of Marine Technology, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia.
Department of Ocean Engineering, Faculty of Marine Technology, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia.
The airflow through the main rotor blade system of a helicopter is still not exceedingly well understood owing to its obscurity in aerodynamics. It is prognosticated that helicopter wakes can be significantly greater than those formed by a fixed wing aircraft of the same weight. Nuisance incidents such as brownout & noises are engendered from rotor wake. Study through flow visualization plays a key role in understanding the airflow distinctiveness and vortex interaction of a helicopter rotor blade. Inspecting and scrutinizing the effects of wake vortices during operation is a great challenge and imperative in designing effective rotor system. This study aimed at finding a suitable method to visualize the main rotor airflow pattern of a remote controlled subscale helicopter and seek for the vortex flow at the blade tip. The experimental qualitative data is correlated with quantitative data to perform meticulous study on the airflow behaviour & characteristics along with its distinctiveness generated by the main rotor in various flight conditions. Simulation is also performed in similar conditions to bequeath with comparability between the flow visualization results. Several dissimilar flow patterns were identified throughout the blade span. At the centre of the main rotor hub, the presence of turbulent flow was perceived. This is because of the low energy of air pooled in this region. Conversely, an apparent straight streamline pattern in the middle portion of the rotor blade was noticed as the air in this section encompassed high kinetic energy.
Department of Aeronautics, Automotive and Ocean Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.
Ocean and Aerospace Research Institute, Indonesia.
