Vortex-induced vibration widely regarded as VIV is one of the vital subjects to be dealt with while designing any structure that is subjected to fluid flow. Vortex-Induced Vibration (VIV) is a multifaceted fluid–structure interaction problem. As the fluid flow interacts with the object, energy dissipates at boundary layer because of viscous drag; separation takes place as the flow lacks sufficient kinetic energy as a result vortices are formed at the wake region of the body These vortices disperse periodically from each side of the body and produce the time dependent non-uniform pressures that are distributed around the object and caused vibration.Vortex induced vibration can be observed in many engineering objects , such as offshore structures, production risers, bridges, aircraft control surfaces, thermo wells, engines, heat exchangers etc. Vortex-Induced Vibration (VIV) is one of the challenging issues faced by hydrodynamic engineers while designing riser systems used for extracting oil and gas from sea bed due to its potential ability to cause a high level of fatigue damage in a relatively short period of time. We will discuss this problem along with possible solution. VIV has positive application too. Unlike previous efforts to suppress the vibratory response of vortex induced vibration (VIV) due to its potential destructive nature for structures subjected in a fluid flow, VIVACE was used for harnessing energy from river and ocean currents by enhancing and utilizing VIV. Researches that are being conducted in UTM to understand and solve the problems of VIV in offshore engineering will be discussed. Application of VIV in renewable energy (VIVACE device )and UTM ‘s current effort to use VIV for maximizing harnessed energy at low speed current will also be addressed.
Ocean Thermal Energy Conversion (OTEC) is a clean marine renewable energy using temperature difference between the sea surface and the deep ocean to rotate a generator to produce electrical energy. Indonesia is an equatorial country located at latitudes less than 20 degrees covered by 77 % ocean, thousand islands, strain and many difference of topography. OTEC is very compatible build in Indonesian. This paper discussed few potential areas of OTEC to be applied in Indonesia such as Sumatera Barat, Sulawesi Utara, Maluku Utara and South and Papua. The study founded that with the temperatures range 27 - 31 0C and the gradient temperature more than 20 0C, OTEC is solutions of Electricity and Clean Water Crisis at Outer and Remote Islands in Indonesia.
Development in any field has been for long relying on the support from the energy availability, accessibility and affordability. As a result, a growing demand and an inclusive access of energy become inevitable challenges. This is particularty true in Indonesia, which has set energy policy and planning. Ocean energy is a unique potential in this context and needs a unique approach to develop that potential. An effort of prototyping industry on ocean energy has been promoted and proposed to ensure that Indonesia is able to untap its ocean energy potential, and in the same time is able to prepare sufficient capacity of national industry of relevance. This keynote speech provides with overview the status of ocean energy development in Indonesia and an approach towards prototyping industry on ocean energy.
National Energy Council, Indonesia & Ocean Engineering, ITS, Indonesia
Because a pusher and barge system (P/B) can be divided into a pusher and a barge(s), the pusher does not need to wait for the completion of loading/unloading, and it can start a next voyage soon after arriving. Therefore, a good transportation efficiency can be expected. In these days, a P/B is also available to a sea-going service by developing a mechanical connection which enabled a P/B to achieve the seaworthy performance in waves. However, there is a concern that the navigation speed is usually less than same-size cargo ships. It may be due to significant vortices generated in the gap at the connection, but the mechanism is still unclear. From this viewpoint, in this study, CFD analysis was carried out to investigate the resistance performance associating with the flow and pressure fields around the pusher and barge, especially with focus on the gap between them. We discussed the unique change of the resistance characteristic depending on the barge load conditions.
Graduate school of Engineering, Hiroshima University, Japan
Shocks by waves, slamming, of the wet deck (the bottom of inter-hull structure) is a specific disadvantage of all multi-hull ships. It means the decreasing of such slamming is an important problem of a multi-hull ship designing and creation. The problem is divided by two parts: motion mitigation and shock elimination. Some methods of longitudinal motion mitigation of various multi-hulls are examined and compared. In addition, some methods of shock pressure decreasing are shown too. As the results, some general and particular recommendations are proposed.
In offshore drilling, requires an analysis of buoyancy which is owned by the rig. The magnitude of the platform’s buoyancy affected by the volume of total column which are submerged below sea level. The more volume columns submerged, the more stable the platform rig stands. The buoyant force will hold two loads on the rig, the static load and dynamic load. Static load is the overall load of the rig, while the dynamic load is a load of the drillstring to be used in the drilling process. Maerks Discoverer is a semi-submersible rig with 4 coloum and will conduct offshore drilling in the Gulf of Mexico. The planned target depth is 18,000 ft (True Vertical Depth), with drillpipe length for 12,000 ft and 6,000 ft drillcollar. With the formation pressure gradient of 0,465 psi/ft, the density of the mud is 10.54 ppg. Drilling is done with 4 drilling trajectory. Its also use ORQ mooring chain type with a diameter of 2 ¾ "by 4 units that have a tension load of 880 tons that can hold the submerged part so that a constant column during the drilling process that is as high as 15 m.
Department of Petroleum Engineering, Faculty of Mineral Technology, Univesitas Pembangunan Nasional “Veteran” Yogyakarta, Indonesia
Instability of a towed ship presented in the form of her unstable yaw motion may lead to serious accident especially at the restricted waterways such as colliding with other ships or onshore structures. To stabilize this unsteady yaw motion, a comprehensive investigation is then required to ensure a safety of ship's towing navigation. This paper presents a computational fluid dynamic (CFD) approach to analyse yaw motion characteristics of a towed ship incorporated with an asymmetrical bridle towline model. Several towing parameters such as towing’s angles and speeds have taken into account. Here, a towed ship or barge in then called as 1B is employed in this simulations. The results revealed that the subsequent increase of towing's angle dealt with a better yaw motion of 1B indicated by sufficient reduction of her sway motion associated with more steady yaw motion of a towed ship.
Maritime Technology, School of Ocean Engineering, Universiti Malaysia Terengganu, Terengganu, Malaysia
Instability of a ship towing system indicated by vigorous yaw motion of a towed ship may reduce the safety of the navigation especially in the restricted with heavy congestion waterways. To stabilise this towing system, a comprehensive investigation on a towline configuration is therefore required. This paper presents Computational Fluid Dynamic (CFD) approach to analyse the unsteady yaw motion characteristic of a towed ship using symmetrical bridle towline. Several towing parameters such as various towing point locations on the symmetrical bridle towline and towline lengths have been taken into account. Here, a towed ship designates as 1B (barge) is employed in the simulations. The results revealed that the subsequent increase of towing point location on the symmetrical bridle towline will reduce significantly her unsteady yaw motions. In addition to longer towline, it gradually leads to have better course stability.
Maritime Technology, School of Ocean Engineering, Universiti Malaysia Terengganu, Terengganu, Malaysia
This study aims to develop a dynamometer for measuring cutting force at process of turning. Dynamometer can measure axial and tangential forces. Dynamometer development includes design, manufacture, calibration, and dynamometer testing. Dynamometer design is adjusted with lathe type G. D. W LZ 350 in the laboratory of Engineering Technology Production Technology University of Riau, and designed and analyzed well, after the manufacture of electrical devices and mechanical dynamometer. Next is the calibration process to determine the multiplier factor for tangential and axial forces. Final step is process of testing dynamometer at lathe machine. Machining parameters used with rounds 450 Rpm, feeding, 0,11; 0,22; 0,33 mm/Rev, and depth of cut 0,2; 0,3; 0,4 mm. Dimension of dynamometer is 75 mm × 40 mm × 40 mm. Maximum force that dynamometer can measure is 500 N for axial and tangential force. The highest value for tangential force is 389,2 N and the value for axial force is 100,95 N.
Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
This research focus on the development of dynamometer type four profile-H plate for a measurement axial and tangential forces on Lathe Machine. The dynamometer consists of mechanical parts and electrical parts. Mechanical components are designed with maximum force 500 N. Dinamometer analyzed using autodesk inventor 2015 software. Dynamometer based strain gauge as strain sensor, HX-711 module, arduino uno, data logger and LCD as electronic component. The results obtained from the measurement of the dynamometer are displayed on the LCD in units of Newton (N) and can be stored on the data logger. Calibration on the dynamometer is performed to determine the sensitivity of the dynamometer and also to determine the calibration factor. The dynamometer testing using variation machining parameters. The dimension of profile-H plate is length 25 mm, width 5 mm, and thick 3 mm.. The Highest value for tangential force is 428.41 N and the value for Axial Force is 109.31 N.
Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
The mechanical behavior of oil palm empty fruit bunch (OPEFB) reinforced polymer composites-polymeric foam sandwich panels are treated as experimental investigation for side body molding appliance. In this research, oil palm empty fruit bunch (OPEFB) fiber will be processed as polymeric foam mixture. This material is subsequently used for the sandwich structure of the impact absorption sandwich panels on the motor vehicle supporting components. OPEFB that has been obtained and then grab the fiber by cut and separated from the OPEFB rod. The separated fibers were treated. It could be know how OPEFB fiber reinforced polymer composites sandwich panels has energy absorption. The experiment is conducted by means of static test. The mechanical behavior of OPEFB fiber reinforced polymer composites-polymeric foam sandwich panels was performed. The microstructure was observed using SEM observation in order to better understand damage mechanism. Based on the static uniaxial tensile and flexural loading results, the mechanical behavior was determined and it was found that fiber treatment influence the tensile and flexural strength of OPEFB fiber reinforced polymer composites-polymeric foam sandwich panels.
Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
This study aims to manufacture a dynamometer type four square plate that can measure tangential and axial force on lathe machine. The dynamometer consists of mechanical and electrical components. The mechanical components are designed and analyzed with a maximum force of 500 N using autodesk inventor 2015 software. Electrical components based on strain gauge sensors for reading strain on mechanical components and connected to HX-711 module as amplifier then forwarded to Arduino Uno to process data and display the results at LCD and the results can be stored on the data logger. For optimal results the dynamometer needs to be calibrated and determine the calibration factor. The machining parameters used during the dynamometer testing process are 450 rpm rotation, Feeding 0.11; 0.22; 0.33 mm / round and depth of cut 0.2; 0.3; 0.4 mm. The dimension of strain rod is 7 mm and length 40 mm. The highest value measurement dynamometer for tangential force is 306.97 N and axial force is 72.91 N.
Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
One method to convert biomass as renewable energy sources, in this case is oil palm empty-fruit-bunch (OPEFB), is biomass gasification. Gasification has advantages as energy conversion method because the energy produced is higher with lower pollutants than the others methods. One of gasifier types that is suitable to reduce tar content and high water content in OPEFB is two stage gasifier. This type is believed to have high efficiency (92-97%) with tar levels at syngas < 25 mg/Nm3. This study is intended to obtain the design of the combustion chamber on a suitable reactor for the biomass gasification of OPEFB, which is carried out with perform simulation of the fluid flow velocity distribution, temperature distribution, pressure distribution, gas and tar produced in the reactor by varying the dimensions of a classic venturi.
Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
