Journal Articles

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    Numerical study on maneuvering a container ship in shallow water waves /
    (IJIRSS, 2023-09-15) Mallampalli, Premchand; Janardhanan, Sheeja; Karottu, KesavadevVarikattu; Ommi, Gnaneswar
    Numerous practical and mathematical techniques have been piloted to study ships’ behavior in deep water conditions with and without waves, and shallow water conditions without waves, while only limited investigations have been carried out to assess ships’ behavior in shallow waters with wave conditions as the flow around the stern regionandappendages and the interaction effects are intricate. Therefore, this study attemptsto understand the infrequently explored subset of a vessel’s behavior in regular waves in shallow water conditions(channel depth to ship draft ratio taken as 1.5). A container ship (S175) model scaledat 1:36 was the subject of a numerical study inwhich it was subjected to static and dynamic maneuver simulations in head sea conditions. The waves were induced using the dispersion relationship of waves in a given depth. The trends of forces and moments acting on the hull while undergoing maneuvering motions were obtained using a smooth particle hydrodynamics-based computational fluid dynamics solver. The resulting periodic trends of forces and moments were analyzed using the Fourier series method to extract the Fourier coefficients and,in turn,calculate the hydrodynamic derivatives. The trajectories in turning circle and zigzagmaneuverswere also simulated using a MATLAB code. The results demonstrate an increase in trajectory parameters and improvement in counter maneuverability owing to the complex flow physics around the hull whenencountering regular waves in shallow water conditionscompared to waves in deep watersand a lack of waves in shallow waters.
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    Shape improvisation of the solar panels on the roof of an electric vehicle /
    (Springer Nature, 2021-06-15) Janardhanan, Sheeja
    It is a well-known fact that bluff body appendages induce augmented drag on a vehicle. Hence, aerodynamic design is inevitable for vehicles for better power and performance. The present work is focused on transforming the present shape of the SCMS School of Engineering and Technology’s solar electric vehicle’s solar roofing from a bluff model to aerodynamic. Computational fluid dynamics studies are carried out on the present shape. The top of the vehicle, housing of the solar panel, is chamfered in steps and a new shape is evolved at ensuring an aerodynamic design. Three different shapes are studied in the present work. The one with minimum drag is suggested for the vehicle. The reduction in the area of the solar panels due to the shape improvisation is compensated for by increasing the surface area to retain the same power input. The proposed new shape is found to reduce the overall drag of the vehicle.
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    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.
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    Antifouling paint schemes for green ships
    (Ocean Engineering, 2019) Mukherjee, A.; Madhu, Joshi; Misra, S. C.; Ramesh, U. S.
    Recent advances in antifouling (AF) paints in general prevent fouling in about 95% of the vessel's immersed surface. However the remaining area which amounts to 5% or less of the total area does get fouled. Although this level of fouling has marginal impact on the routine performance of the vessel it is a predominant vector for the transmigration of invasive species which is now a serious environmental concern. Virtually all ocean going vessels are coated with antifouling paints predominant among them are “Self polishing coatings”. CFD analysis conducted on various types of vessels have indicated that there are certain “hotspots” where the polishing rates are exceedingly high and would polish the AF paints at a much faster rate and ultimately result in the failure of the AF coating. A possible solution to this issue is to first identify these hotspots and suitable paint schemes/formulations are to be applied in such areas. An experimental procedure utilizing a “drum-test” apparatus can be used to compute the coating thicknesses based on wall shear stresses. Such painting schemes would prevent the premature failure of the AF coating in general and significantly reduce the risk of transmigration of invasive species in particular.
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    Shape improvisation of the solar panels on the roof of an electric vehicle
    (Spingerlink, 2021-08) Sekhar, Gautam C.; Krishna, D Gokul; Abhimanue, H.; Meeran, Fadil K; Janardhanan, Sheeja
    It is a well-known fact that bluff body appendages induce augmented drag on a vehicle. Hence, aerodynamic design is inevitable for vehicles for better power and performance. The present work is focused on transforming the present shape of the SCMS School of Engineering and Technology’s solar electric vehicle’s solar roofing from a bluff model to aerodynamic. Computational fluid dynamics studies are carried out on the present shape. The top of the vehicle, housing of the solar panel, is chamfered in steps and a new shape is evolved at ensuring an aerodynamic design. Three different shapes are studied in the present work. The one with minimum drag is suggested for the vehicle. The reduction in the area of the solar panels due to the shape improvisation is compensated for by increasing the surface area to retain the same power input. The proposed new shape is found to reduce the overall drag of the vehicle.