CFD tools have an important benchmark problem, and the lid-driven cavity is one of the most outstanding tools. This paper presents the benchmark tool for CFD simulation of a lid-driven cavity, examining the particular...
CFD tools have an important benchmark problem, and the lid-driven cavity is one of the most outstanding tools. This paper presents the benchmark tool for CFD simulation of a lid-driven cavity, examining the particular case of top-and-bottom moving boundary conditions. The governing equation that is used is an unsteady Navier-Stokes equation in a primitive variable formulation. The solution method is implicit finite difference with staggered grid. The result is a symmetrical vortex with half top and lower part. The Reynolds number was varied between 100, 500,1000, 4000 and 10000. In this paper we also present the secondary vortex in some circumstances. The velocity profile in a quarter, half and three-fourth full x and y axis is also presented.
Segara Anakan is the largest estuary ecosystem in the south coast of java Island. There are three major rivers, and at least seven creeks, discharge their flow to the estuary. Lands in the vicinity of the estuary are ...
Segara Anakan is the largest estuary ecosystem in the south coast of java Island. There are three major rivers, and at least seven creeks, discharge their flow to the estuary. Lands in the vicinity of the estuary are fertile, and utilize by community as agriculture land. Nowadays, community must face saltwater intrusion problem into the rivers. The aim of this study is to investigate the saltwater intrusion length into the river in the vicinity of estuary, focused on three main rivers, Citanduy, Cibeureum, and Cikonde. The saltwater intrusion is simulated using Surfacewater Modelling System (SMS), with freshwater discharge and the seawater level as main parameter. simulation result shows that the rivers are highly risk to saltwater intrusion, especially during the dry season. The rivers become mostly brackish environment along the year. The lowland agricultures are highly risk to crop yield failure, especially for the paddy field which located between Citanduy and Cibeureum River. The adaptation scheme should be applied to overcome the problem.
The current use of energy has begun to lead to the use of renewable energy from nature, one of which is wind energy. A gust of wind can be extracted into new energy using the help of wind power plants. VAWT (Vertical ...
The current use of energy has begun to lead to the use of renewable energy from nature, one of which is wind energy. A gust of wind can be extracted into new energy using the help of wind power plants. VAWT (Vertical Axis Wind Turbine) is a type of wind turbine whose main axis is arranged transversely to the direction of the wind and its main components are located at the base of the turbine. This study aims to determine the magnitude of the effect of variations in wind velocity and the number of blade levels of Hybrid turbines on turbine performance and aims to determine which variation is the most effective in extracting wind energy. This study uses a quasi-experimental method on the object of research in the form of vertical axis wind turbines of the Darrieus, Savonius and Hybrid types with variations in wind velocity of 3, 5 and 7 m/s and variations in the number of levels of one and two levels of Hybrid blades. The research data was obtained through simulation with the help of ANSYS 17.0 software using the CFD method (Computational fluid dynamics). The output of this research is the value of power, torque, tangential speed and efficiency generated by the wind turbine. The results showed that the wind velocity and the number of blade levels greatly affect the performance of the wind turbine. In this study, it was found that from the results of simulation testing using the CFD method, the best efficiency value was found in the one-stage Hybrid Darrieus-Savonius turbine at a wind velocity variation of 7 m/s of 3,31256% and Hybrid Darrieus-Savonius. Savonius two levels at 5 m/s wind velocity variation of 4,53786%.
Maintaining the PEM Fuel Cell under the optimum operating conditions is a challenging task which requires the careful design of efficient controllers for most significant parameters. Identification of the most relevan...
Maintaining the PEM Fuel Cell under the optimum operating conditions is a challenging task which requires the careful design of efficient controllers for most significant parameters. Identification of the most relevant set of parameters for control and its validation is very critical in developing stable and reliable PEM FC systems. This work involves the validation of optimum input parameter values obtained from a set of Neuro-Fuzzy Controllers designed for a 500W PEMFC. The simulation was made in Matlab/Simulink platform and tested under various operating conditions to obtain optimal electrical performance of 25V at 20A load condition is used for the study. Validation is done using the machine- learning algorithm, Tertius. The basic design for validation was developed in WEKA (Waikato Environment for Knowledge Analysis) platform and the same was implemented in a java environment. As being a single attribute oriented algorithm in machine learning suite, Tertius validates the designed model and provides accurate prediction. Performance of the model has also been analyzed using the area under the ROC curve.
Microservices is an architecture that is popularly used, at least in the last five years. This architecture breaks down large applications into smaller applications that stand alone so that they can run when there is ...
Microservices is an architecture that is popularly used, at least in the last five years. This architecture breaks down large applications into smaller applications that stand alone so that they can run when there is a crash or error in one of the services. Therefore, implementing these microservices is often carried out on applications with a high level of access. E-Government is an area that can apply this architecture because many government services are accessed by the public simultaneously, thus allowing these services to be down. This study will analyze existing government applications to see what services are available and create an environment to simulate those services. The simulation aims to see if one or two services are currently unusable due to repairs, then other services can still be used. All services will be a single application with a microservices architecture. The test carried out is load testing to measure service resilience when receiving requests from users. These tests obtained 132.2 requests per second with an average error of 17% for 800 users per service. In addition, because each service is built in a different place, if one service crashes or does not respond, the other services can still run. For further research, it is necessary to add security to the microservices architecture because e-government usually requires a high level of security. The security in cloud services is also insufficient.
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