Browsing by Author "Godey, Avinash"

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A study for validating, rectifying and optimizing the flow in the test section of a circulating water channel /
(Journal of Naval Architecture and Marine Engineering, 2021-12-31) Godey, Avinash
The Circulation Water Channel (CWC) is an experimental facility available at Indian Maritime University, Visakhapatnam Campus. A study for comparing the flow pattern and velocity in the test section, for different configurations of the CWC, is complex. To study the flow, a physical model of the CWC, with different configurations, should be made, which in overall is a complicated and time-consuming exercise. But this difficulty can be overcome through using Computational Fluid Dynamics (CFD) analysis, as in this study, where a CFD analysis is done using ‘STAR-CCM+’ software. A CFD model of the existing CWC [corresponding to the 1:4 scale setup at IMUV], is first made, and its validity is checked, by comparing the results of the CFD analysis, against those results obtained from the experimental analysis. On successfully validating the results, modifications are suggested for rectifying the disturbance which is present in the test section. The test section is the area in the CWC where experimental activities are carried out. In order to carry out the experiments with a certain degree of accuracy, it is important to have a smooth streamlined flow in the test section. To ensure this, a honeycomb structure is positioned such that the flow enters the test section through the honeycomb, which streamlines the flow. On successfully rectifying the disturbance, studies are carried out to improve the streamlined flow in the test section, for which, different configurations of honeycomb structure are studied. The optimum honeycomb structure, which produces a smooth flow in the test section of a CWC is found out, by conducting analyses for different shapes - i.e. for shapes ranging from rectangular to hexagonal and circular, against different inlet velocities.
CFD analysis for a ballast free ship design
(NISCAIR-CSIR, India, 2014-11) Godey, Avinash; Misra, S. C.; Sha, O. P.
Shipping transfers approximately 3 to 5 billion tonnes of ballast water internationally each year. This ballast water transferred between different ports is a serious environmental problem. There are many marine species like bacteria, small invertebrates and the eggs, etc., that are carried in ship’s ballast water which are small enough to pass through a ship’s intake at ports and when discharged, lead to severe ecological problems. To overcome this, a concept of ballast free ship has been developed in which ballast water exchange and treatment is avoided by providing flow-through longitudinal pipes in the double bottom instead of conventional ballast tank. During the design of the ballast free ship, different hull forms have been generated with various hull shapes of the vessel which have been studied with regard to hydrodynamic behaviour. Finally one hull form has been selected for further study. The present work aims to estimate the penalty on resistance using CFD techniques using SHIPFLOW® software. These results are validated by model experiments for the conventional and the proposed ballast Free form at loaded and ballast drafts in the Hydrodynamics Laboratory of the Department of Ocean Engineering and Naval Architecture, IIT Kharagpur.
Development of a ballast free ship design
(International Journal of Innovation Research & Development, 2012-12) Godey, Avinash; Misra, S. C.; Sha, O. P.
Shipping transfers approximately 3 to 5 billion tonnes of ballast water internationally each year. Ballast water discharges non-native species leading to severe ecological problems. The present work aims at a design solution into the ballastless ship in which ballast water exchange and treatment is avoided by providing flow-through longitudinal pipes in the double bottom instead of conventional ballast tanks. During the design of the ballast less ship, different hull forms are generated with altering the hull shape in forward and aft out of which one was finalised. In addition to change in hull form the internal tank arrangement has been changed so that the propeller immersion and the minimum draft required in the ballast condition is achieved. Structural arrangement for the mid ship section was proposed for the modified hull form of ballast less ship as well as data on valves had been collected for the flow through condition. Finally, resistance tests were conducted on equivalent models of scale ratio 1:71 for the conventional and the proposed ballsatless form at the loaded and ballast drafts in the Hydrodynamic Towing Tank of the Department of Ocean Engineering and Naval Architecture, IIT Kharagpur. The model experiments on ballast less ship show an increase in resistance in ballast draft when compared to a conventional tanker due to the flow through pipes in double bottom.
Study of flow in the test section of a circulating water channel by varying the honey comb cross-section
(Indian Maritime University, Visakhapatnam, 2019) Kiran George, Varghese; Vinay Gopi, Nair; Godey, Avinash; Sunil Kumar, PG.
The Circulation Water Channel (CWC) is a research facility available at Indian Maritime University, Visakhapatnam Campus. The investigation of a flow, in different configurations of the CWC set up, for obtaining a required flow velocity in the test section, is complex. To study the flow, a physical model of the CWC, with different configurations, should be made, which in overall is a complicated and time-consuming exercise. But this difficulty can be overcome through using Computational Fluid Dynamics (CFD) analysis, as in this study, where a CFD analysis is done using ‘STAR-CCM+’ software. A CFD model of the existing CWC [corresponding to the 1:4 scale setup at IMUV], is first made, and its validity is checked, by comparing the results of the CFD analysis, against those results obtained from the experimental analysis. The test section is the area in the CWC, or its CFD model, where the experimental activities are carried out. It is important to have a smooth streamlined flow in the test section, and to ensure this, a honeycomb structure is placed such that the flow enters the test section through the structure. The optimum honeycomb structure, which produces a smooth flow in the test section of a CWC, is found out, by conducting analyses for different shapes - i.e. for shapes ranging from rectangular to hexagonal and also for different inlet velocities