Journal of Waterway, Port, Coastal, and Ocean Engineering, 2020
AbstractThe lateral separation ratio (S/D) between the twin pontoons of a floating breakwater (TP... more AbstractThe lateral separation ratio (S/D) between the twin pontoons of a floating breakwater (TPFB) is one of the prominent factors that attenuate wave energy transmission and reflection. In fact,...
Hydrofoil ship usually experiences high resistance and excessive heave and pitch that may lead to... more Hydrofoil ship usually experiences high resistance and excessive heave and pitch that may lead to downgrade her seakeeping performance. Therefore, a reliable investigation on prediction of a seakeeping performance of a hydrofoil ship in head-seas is obviously required. To achieve this objective, an analysis of Computational Fluid Dynamic (CFD) approach on hydrofoil ship motion is then proposed. Several parameters such as angle of stern foil and Froude Number have been accordingly taken into account in the simulation, where the fore foil angle is constantly 5 . In general, the results revealed that the increase of the stern foil angle was proportional to the heave motion of the hydrofoil ship. As compared to the magnitude of the stern foil angle of 5 and 10 , the heave motion of the hydrofoil ship has sufficiently decreased at the stern foil angle of 7.5, which leads to have a better seakeeping performance. Furthermore, the subsequent increase of Froude number pointing towards reduct...
IOP Conference Series: Earth and Environmental Science
Looking forward to the abovementioned conditions, this research is needed to elaborate on the eff... more Looking forward to the abovementioned conditions, this research is needed to elaborate on the effects of the reclamation to the marine resources in Teluk Lamong Multipurpose Port Terminal as the reclaimed product. In order to describe the impact of the port development, this study will analyze the shoreline changing, the current pattern modeling, as well as the Total Suspended Solid (TSS) modeling using the remote sensing data. The several numbers of expected objectives through this study are to get the set of scientific information on the shoreline changing in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, to get the figure of current pattern in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, and to elaborate TSS concentration through the modeling approach in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020. Hence, there is a set of methodologies and tools to cooperate with the information before and after the reclama...
Due to the increasing of fuel prices and volatile of environmental regulations, it is a challenge... more Due to the increasing of fuel prices and volatile of environmental regulations, it is a challenge for Naval Architects to design a ship dealing with an optimum ship’s total resistance. The conventional design of catamaran hull has not satisfied yet to reduce the ship’s total resistance. This paper presents a numerical investigation into gaining sufficient reduction of the ship’s total resistance of catamaran through optimizing her hull form. To achieve this research objectives, a numerical optimization modelling coupled with a Computational Fluid Dynamics (CFD) approach has been successfully conducted. Several parameters such as length, beam and draft of catamaran hull have been taken into account towards reducing the ship’s total resistance. Here, the simulation constraints are applied to obtain the optimum dimension, where the length, beam and draft of the catamaran hull were optimized within the range of 1.2 m to 1.5 m, 0.11 m to 0.14 m and 0.07 m to 0.08 m, respectively. In gene...
The characteristics of the fore and aft foils at the various angles of attack incorporated with f... more The characteristics of the fore and aft foils at the various angles of attack incorporated with forward velocities have been vulnerable to induce strong nonlinearities to dynamic lift force and ship resistance. Then, a computational simulation is necessarily required to predict their performances in the calm water condition. This paper presents a computational investigation of the hydrofoil ship on predicting lift and ship’s resistance using fluid dynamic (CFD) simulation approach. Several parameters such as Froude numbers and the angle of attacks both of fore and aft foils have been accordingly taken into account. The results revealed that the subsequent increase on angle of attack of fore and aft foils was directly proportional to the lift force and the ship’s resistance. In addition, the lift force of the aft and fore foils with the angle of attacks of 10 degrees and 5 degrees, respectively, resulted in the significant increase of the lift force and the ship’s resistance. However...
Education and culture play an important role in developing the noble values of a nation that have... more Education and culture play an important role in developing the noble values of a nation that have an impact on the formation of human character. However, the reality is that cultural values and character are increasingly eroding based on current phenomena. For this reason, it is necessary to have teaching materials that integrate character and cultural education to prevent this from being eroded. One that can bridge between culture and character-based education is ethnomathematics. For this reason, this study aims to develop teaching materials in the form of the friend app application to improve student character education through good quality puppet characters seen from the criteria of validity and practicality. This type of research is Research and Development (R&D) which refers to the ADDIE development model (Analyze, Design, Development, Implementation, Evaluation). This research was conducted in class VIII SMP Negeri 2 Godean. In addition to students, the source of data in this...
IOP Conference Series: Earth and Environmental Science, 2021
In presence of complex-hydrodynamic interaction between water wave and moving structure, a reliab... more In presence of complex-hydrodynamic interaction between water wave and moving structure, a reliable method that can analyse nonlinear phenomena is necessarily required. This paper presents numerical investigation of a moored floating breakwater using computational fluid dynamic (CFD) approach. The mathematical model is based on the extended Reynolds Average Navier-Stokes (RANS) solver for solid-porous obstacle. A high amplitude wave with several wave periods were deliberately considered in the simulation to allow nonlinear wave effects on the floating structure such as wave breaking, overtopping, including viscous friction. Here, the two fluid calculation method for interface boundary between water and air is proposed to capture the complex free surface changes. In addition, the fractional average volume obstacle representation (FAVOR) using partial cell treatment method is employed to simulate the motion of breakwater boundary on the free surface. Approximations and validations on ...
IOP Conference Series: Earth and Environmental Science, 2021
A towed barge is one of the typical sea transportation systems that is basically composed of towi... more A towed barge is one of the typical sea transportation systems that is basically composed of towing and towed ships connected to each other by a tow rope. During a towing operation exposed to rough sea condition, the risk of collision and breakage of a tow rope may be high and the consequences serious. This paper describes an experimental investigation of a towed barge’s motions in heading waves. The effects of various lengths and the configuration of tow ropes incorporated with various loading conditions of the towed barge have been taken into account. Here, three tow-rope lengths were used, namely 1L, 1.5L, and 2L; meanwhile, the two tow-rope configurations i.e., Straight-Tow (ST) and V-Tow (VT) models were applied and incorporated with 50% and 100% of the loading conditions of the towed barge. Regardless of the tow-rope models of ST and VT, the results revealed that the towed barge’s motion responses were generally proportional to the increase of the towline lengths and the towed...
In this paper, a constraint Genetic Algorithm is used for the purpose of mooring pattern optimiza... more In this paper, a constraint Genetic Algorithm is used for the purpose of mooring pattern optimization. The Genetic Algorithm is applied through a mathematical formulation which is introduced to define a typical mooring system optimization problem. The mathematical formulation is used in a case study on a spread moored crane barge, operating in the vicinity of a jacket type platform, in order to minimize its surge motions towards the platform. For this purpose, a set of criteria regarding clearances between anchors and seabed preinstalled facilities (pipelines), and also between the crane barge and the jacket platform are presented and considered. An automatic process of repetitive analyses implementing a MATLAB code as an interface between the Genetic Algorithm and a mooring system analysis program is used, and an optimum solution is resulted by performing 4000 quasi-dynamic analyses in time domain. The effectiveness of the Genetic Algorithm in leading to an optimum mooring system p...
Journal of Naval Architecture and Marine Engineering
The utilization of the existing breakwater constructions into wave energy conversion has been oft... more The utilization of the existing breakwater constructions into wave energy conversion has been often adopted to rendering a revenue of the capital cost of investment. The paper has contributed to viable concept of a new integration design through more effectively capturing wave-overtopping which finally converts into electrical energy. This design is hereafter called Overtopping Breakwater for Energy Conversion (OBREC). The development of an experimental test of the current OBREC has been conducted to obtain a proper ramp shape through evaluating the amounts of the wave-overtopping discharges into the reservoir incorporated with wave-reflection coefficients. To achieve the objective, several geometry ramps such as linear, convex, concave and cubic shapes have been experimentally investigated at the National Research Institute Malaysia (NAHRIM) laboratory. The experimental study showed that the cubic-ramp shape has resulted in more significant amount of the wave-overtopping discharge ...
Journal of Waterway, Port, Coastal, and Ocean Engineering, 2020
AbstractThe lateral separation ratio (S/D) between the twin pontoons of a floating breakwater (TP... more AbstractThe lateral separation ratio (S/D) between the twin pontoons of a floating breakwater (TPFB) is one of the prominent factors that attenuate wave energy transmission and reflection. In fact,...
Hydrofoil ship usually experiences high resistance and excessive heave and pitch that may lead to... more Hydrofoil ship usually experiences high resistance and excessive heave and pitch that may lead to downgrade her seakeeping performance. Therefore, a reliable investigation on prediction of a seakeeping performance of a hydrofoil ship in head-seas is obviously required. To achieve this objective, an analysis of Computational Fluid Dynamic (CFD) approach on hydrofoil ship motion is then proposed. Several parameters such as angle of stern foil and Froude Number have been accordingly taken into account in the simulation, where the fore foil angle is constantly 5 . In general, the results revealed that the increase of the stern foil angle was proportional to the heave motion of the hydrofoil ship. As compared to the magnitude of the stern foil angle of 5 and 10 , the heave motion of the hydrofoil ship has sufficiently decreased at the stern foil angle of 7.5, which leads to have a better seakeeping performance. Furthermore, the subsequent increase of Froude number pointing towards reduct...
IOP Conference Series: Earth and Environmental Science
Looking forward to the abovementioned conditions, this research is needed to elaborate on the eff... more Looking forward to the abovementioned conditions, this research is needed to elaborate on the effects of the reclamation to the marine resources in Teluk Lamong Multipurpose Port Terminal as the reclaimed product. In order to describe the impact of the port development, this study will analyze the shoreline changing, the current pattern modeling, as well as the Total Suspended Solid (TSS) modeling using the remote sensing data. The several numbers of expected objectives through this study are to get the set of scientific information on the shoreline changing in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, to get the figure of current pattern in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020, and to elaborate TSS concentration through the modeling approach in Teluk Lamong Multipurpose Port Terminal in the year of 2012 and 2020. Hence, there is a set of methodologies and tools to cooperate with the information before and after the reclama...
Due to the increasing of fuel prices and volatile of environmental regulations, it is a challenge... more Due to the increasing of fuel prices and volatile of environmental regulations, it is a challenge for Naval Architects to design a ship dealing with an optimum ship’s total resistance. The conventional design of catamaran hull has not satisfied yet to reduce the ship’s total resistance. This paper presents a numerical investigation into gaining sufficient reduction of the ship’s total resistance of catamaran through optimizing her hull form. To achieve this research objectives, a numerical optimization modelling coupled with a Computational Fluid Dynamics (CFD) approach has been successfully conducted. Several parameters such as length, beam and draft of catamaran hull have been taken into account towards reducing the ship’s total resistance. Here, the simulation constraints are applied to obtain the optimum dimension, where the length, beam and draft of the catamaran hull were optimized within the range of 1.2 m to 1.5 m, 0.11 m to 0.14 m and 0.07 m to 0.08 m, respectively. In gene...
The characteristics of the fore and aft foils at the various angles of attack incorporated with f... more The characteristics of the fore and aft foils at the various angles of attack incorporated with forward velocities have been vulnerable to induce strong nonlinearities to dynamic lift force and ship resistance. Then, a computational simulation is necessarily required to predict their performances in the calm water condition. This paper presents a computational investigation of the hydrofoil ship on predicting lift and ship’s resistance using fluid dynamic (CFD) simulation approach. Several parameters such as Froude numbers and the angle of attacks both of fore and aft foils have been accordingly taken into account. The results revealed that the subsequent increase on angle of attack of fore and aft foils was directly proportional to the lift force and the ship’s resistance. In addition, the lift force of the aft and fore foils with the angle of attacks of 10 degrees and 5 degrees, respectively, resulted in the significant increase of the lift force and the ship’s resistance. However...
Education and culture play an important role in developing the noble values of a nation that have... more Education and culture play an important role in developing the noble values of a nation that have an impact on the formation of human character. However, the reality is that cultural values and character are increasingly eroding based on current phenomena. For this reason, it is necessary to have teaching materials that integrate character and cultural education to prevent this from being eroded. One that can bridge between culture and character-based education is ethnomathematics. For this reason, this study aims to develop teaching materials in the form of the friend app application to improve student character education through good quality puppet characters seen from the criteria of validity and practicality. This type of research is Research and Development (R&D) which refers to the ADDIE development model (Analyze, Design, Development, Implementation, Evaluation). This research was conducted in class VIII SMP Negeri 2 Godean. In addition to students, the source of data in this...
IOP Conference Series: Earth and Environmental Science, 2021
In presence of complex-hydrodynamic interaction between water wave and moving structure, a reliab... more In presence of complex-hydrodynamic interaction between water wave and moving structure, a reliable method that can analyse nonlinear phenomena is necessarily required. This paper presents numerical investigation of a moored floating breakwater using computational fluid dynamic (CFD) approach. The mathematical model is based on the extended Reynolds Average Navier-Stokes (RANS) solver for solid-porous obstacle. A high amplitude wave with several wave periods were deliberately considered in the simulation to allow nonlinear wave effects on the floating structure such as wave breaking, overtopping, including viscous friction. Here, the two fluid calculation method for interface boundary between water and air is proposed to capture the complex free surface changes. In addition, the fractional average volume obstacle representation (FAVOR) using partial cell treatment method is employed to simulate the motion of breakwater boundary on the free surface. Approximations and validations on ...
IOP Conference Series: Earth and Environmental Science, 2021
A towed barge is one of the typical sea transportation systems that is basically composed of towi... more A towed barge is one of the typical sea transportation systems that is basically composed of towing and towed ships connected to each other by a tow rope. During a towing operation exposed to rough sea condition, the risk of collision and breakage of a tow rope may be high and the consequences serious. This paper describes an experimental investigation of a towed barge’s motions in heading waves. The effects of various lengths and the configuration of tow ropes incorporated with various loading conditions of the towed barge have been taken into account. Here, three tow-rope lengths were used, namely 1L, 1.5L, and 2L; meanwhile, the two tow-rope configurations i.e., Straight-Tow (ST) and V-Tow (VT) models were applied and incorporated with 50% and 100% of the loading conditions of the towed barge. Regardless of the tow-rope models of ST and VT, the results revealed that the towed barge’s motion responses were generally proportional to the increase of the towline lengths and the towed...
In this paper, a constraint Genetic Algorithm is used for the purpose of mooring pattern optimiza... more In this paper, a constraint Genetic Algorithm is used for the purpose of mooring pattern optimization. The Genetic Algorithm is applied through a mathematical formulation which is introduced to define a typical mooring system optimization problem. The mathematical formulation is used in a case study on a spread moored crane barge, operating in the vicinity of a jacket type platform, in order to minimize its surge motions towards the platform. For this purpose, a set of criteria regarding clearances between anchors and seabed preinstalled facilities (pipelines), and also between the crane barge and the jacket platform are presented and considered. An automatic process of repetitive analyses implementing a MATLAB code as an interface between the Genetic Algorithm and a mooring system analysis program is used, and an optimum solution is resulted by performing 4000 quasi-dynamic analyses in time domain. The effectiveness of the Genetic Algorithm in leading to an optimum mooring system p...
Journal of Naval Architecture and Marine Engineering
The utilization of the existing breakwater constructions into wave energy conversion has been oft... more The utilization of the existing breakwater constructions into wave energy conversion has been often adopted to rendering a revenue of the capital cost of investment. The paper has contributed to viable concept of a new integration design through more effectively capturing wave-overtopping which finally converts into electrical energy. This design is hereafter called Overtopping Breakwater for Energy Conversion (OBREC). The development of an experimental test of the current OBREC has been conducted to obtain a proper ramp shape through evaluating the amounts of the wave-overtopping discharges into the reservoir incorporated with wave-reflection coefficients. To achieve the objective, several geometry ramps such as linear, convex, concave and cubic shapes have been experimentally investigated at the National Research Institute Malaysia (NAHRIM) laboratory. The experimental study showed that the cubic-ramp shape has resulted in more significant amount of the wave-overtopping discharge ...
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Papers by Ahmad Fitriadhy