Comparison of Remotely Sensed Wind Data over Sulawesi and Maluku Islands Sea Areas

In order to obtain accurate prediction of ocean wind energy, long term data are needed. However, one data sources might not able to provide long duration data. Therefore, the data need to be combined with other sources of data. However, before combining the data, it is important to compare and validate them to confirm their accuracy. In the present study, wind speed data collected by QuikScat and SSM/I (SSMIS) missions are compared and analyzed. QuikScat data were collected by a satellite with the same name, while Special Sensor Microwave Imager (SSM/I) and Special Sensor Microwave Imager Sounder (SSMIS) data are processed and offered by Remote Sensing System (RSS). SSM/I (SSMIS) are passive microwave radiometers carried onboard Defense Meteorological Satellite Program (DMSP). For the comparison, 5 (five) arbitrary positions over Sulawesi and Maluku islands sea areas are chosen for the analyses. For the evaluation purposes, beside time series of daily data from several chosen positions in research location, several statistical parameters are also computed and compared such as mean, standard deviation, root mean square (RMS), correlation coefficient.

Ocean Wind Energy Potential and Analysis at Eastern Indonesia

Hasil Penelitian Unggulan Perguruan Tinggi 2014As an archipelago country with wide sea areas, Indonesia has large ocean wind energy potential. However, in order to optimally explore and utilize this energy, information about distribution, speed and direction of the wind in these areas need to be collected and analyzed. For that purpose, a study is conducted to analyze ocean wind energy at eastern part of Indonesia especially around Sulawesi and Maluku islands. The main wind data are collected from several weather and meteorological stations operating around the islands. Direct measurements in certain locations around the islands are also carried out to correct the obtained wind model from the meteorological stations. Weibull distribution with two parameters is used to represent the characteristic and distribution of the wind model. Several statistical and numerical methods are used to compute the Weibull parameters such as regression analysis, maximum likelihood method (MLM) and method of moment (MOM). The obtained energy density is used to draw a wind energy map for sea areas around these islands

Realistic Design of a Floating Breakwater Design with Moonpools

In an attempt to obtain a 2D floating breakwater model with high performance in wave reflection, genetic\ud algorithm (GA) was combined with boundary element method (BEM) in the previous study. The\ud performance of the obtained model was verified with numerical relations as well as an experiment in\ud towing tank. Moreover, its performance and characteristics in 3D case were also evaluated in the\ud subsequent study. However, because the 3D model is formed by simply extruding the 2D shape in\ud longitudinal direction, it only produces a model with uniform transversal shape which is considered to be\ud less effective and efficient in terms of technical and economical points of view. Consequently, it is needed\ud to modify the model to obtain a more realistic and efficient design without reducing significantly the high\ud performance obtained previously. In the present study, several modifications of the original 3D model are\ud performed which include placing moonpools inside the body. The performance and characteristics of the\ud modified models in terms of wave elevations on the free surface are evaluated at various wavelengths by\ud using higher order boundary element method (HOBEM). The accuracy of the computed results is\ud confirmed with Haskind-Newman and energy conservation relations. From the modifications and\ud evaluations of the models, it could be realized that the moonpools inside the body could be used to obtain\ud a more realistic model without reducing the optimum performance of the original model shape

Movement Analysis of Two Hand Backhand Techniques in Unimed Tennis Field Community Athlets 2021

The aim is to analyze the two handed backhand motion of the athletes of the Unimed Tennis Community in 2021.The research was carried out at the Medan State University Tennis Court (UNIMED) Jln. William Iskandar Pasar V Medan Estate. Data collection was carried out on October 25, 2021. The number of samples in this study amounted to 3 people. This research is a kind of quantitative approach research (non-experimental) by analyzing the motion of the two-handed backhand technique between athletes who are used as comparisons with international athletes as samples using the Dartfish teampro 5.5 software.The percentage of successful movements analyzed using darfish software Two-handed backhand technique, the position of the prefix movement is Very Good (30%), Good (26.66%), Less (40%), Very Poor (6.66%). The position of the implementation movement is Very Good (14.81%), Good (25.92%), Poor (11.11%), Very Less (48.14%). Position of follow up Very Good (12.5), Good (41.66%), Poor (16.66%), Very Less (29.16%)

Analisa Efisiensi Gearbox pada Motor Penggerak Listrik Kapal Nelayan

Gearbox berfungsi sebagai alat untuk melambatkan putaran motor listrik, sehingga diharapkan dapat digunakan untuk menyesuaikan putaran serta mengubah daya atau torsi dari motor yang berputar menjadi tenaga yang lebih besar. Penelitian ini juga bertujuan untuk menganalisa masalah efisiensi dari gearbox sebagai sistem penunjang dalam pengoperasian motor listrik. Pada penelitian dilakukan beberapa variasi tegangan listrik yaitu 60, 110,160, dan 210 Volt. Pengambilan data juga dilakukan dengan menggunakan beban (air) dan tanpa beban. Dari hasil analisa didapatkan hasil bahwa semakin tinggi tegangan listrik yang diberikan pada motor listrik maka semakin besar nilai efisiensi yang didapatkan dimana pada kondisi tanpa beban saat tegangan 210 volt nilai efisiensi gearbox sebesar 99,870%, pada saat kondisi dengan beban (air) saat tegangan 210 volt nilai efisiensi gearbox sebesar 98,887%. Semakin kecil tegangan semakin besar torsi yang dihasilkan dimana pada kondisi tanpa beban saat tegangan 60 volt torsi poros propeller sebesar 1.809 Nm, pada kondisi dengan beban (air) saat tegangan 60 volt 3.361 Nm

Numerical Analysis of an Arbitrary-Shaped Floating Body with HOBEM

paper to be presented in 8th International Conference on Numerical Analysis in EngineeringIn order to analyze a floating body with arbitrary shape, large number of panels should be used to obtain good accuracy results because the whole body must be discretized. In order to obtain high accuracy results with relatively small number of panels, higher order boundary element method (HOBEM) is used to compute an asymmetric model in the present study. The hydrodynamic characteristics of the body in terms of added mass, damping coefficients, wave exciting forces and moments, body motions amplitude, and wave elevations on the free surface are evaluated at various incident wavelengths by HOBEM. HOBEM which is based on the potential flow theory divides the body into a certain number of panels and uses quadratic representation for both the quadrilateral panels and unknown velocity potentials on each panel. The velocity potential on each panel is considered to vary so that high accuracy results can be obtained with small number of panels. The accuracy of the computed results is checked numerically using Haskind-Newman and energy conservation relations. Head and oblique waves cases are analyzed to demonstrate the applicability of the method. From the computation results, the asymmetric effect of the computed model could be shown

Design Optimization and Performance Evaluation of a Floating Breakwater

In order to design an optimal floating breakwater with a high performance in a wide range of frequencies, its characteristics and performance in 2D and 3D cases are analyzed. For obtaining an optimal 2D model shape, an optimization method called Genetic Algorithm (GA) combined with Boundary Element Method (BEM) is employed. The accuracy of BEM analysis is confirmed using numerical relations such as Haskind-Newman and energy conservation relations. Moreover, since the investigated model will be an asymmetric shape, an experiment is also conducted to confirm that the present analysis could treat asymmetric body case correctly. However, because the performance of the obtained 2D model is expected to be different for some extent from real application, the performance of the corresponding model in 3D case is also analyzed using Higher Order Boundary Element Method (HOBEM). 3D Wave effect and its effect to the floating breakwater performance are analyzed and discussed. It is shown from this study that the combination of GA and BEM is effective in obtaining an optimal performance model. Moreover, it is also shown that the 3D wave effect is small on motion amplitudes while the wave elevations are found to be in 3D pattern even for a longer body length

NUMERICAL ANALYSIS OF IRREGULAR-SHAPED FLOATING BREAKWATER

It is known that the floating type of breakwater is more preferable than conventional or fixed-type one especially by considering its economical and technical benefits. However, the common shape of a floating breakwater, which is usually simply a rectangular shape, could only attenuate waves in a limited range of frequency especially in short wavelength region. In longer wavelength region, it will just move following the seawater motions as a small object. In order to address this problem, an irregular-shaped floating breakwater, which utilizes the relative motion of water inside its body, which as a result could attenuate incoming waves in relatively longer wavelength region, needs to be implemented. By analyzing the relation of hydro dynamical and geometrical influences to the performance, the optimal shape and dimension can be obtained. The performance of the models described by performance index (PI) for clear and convenient comparison and assessment. The analysis and numerical computations based on the potential flow theory