Research Publications

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Author: search.filters.author.Sha, O. P.Subject: search.filters.subject.CFD

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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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    Feasibility study and design of shallow draught ore carriers for inland waterways
    (First International Conference IDS 2013, 2013-07) Sha, O. P.; Pallencar, S.; Viswanath, N.; Misra, S. C.
    The surge in iron ore exports from the Indian state of Goa has increased the demand for larger size inland iron ore carries. Operating economic of these inland vessels have resulted in a steady increase in their carrying capacity. However, attempt to increase the deadweight of these vessels has encountered challenges in form of loading and unloading point restrictions, increased squat, sway force and yaw moment at shallow waters. The present work based on a request from ministry of shipping, Government of India, examines the present ore transportation system, the bathymetry of the mandovi and zuari rivers and the operating economics of the barges ranging from 750 to 3000 tonnes deadweight capacity. A new improved design for 3000 tonnes dead weight barge is presented. Alternate stern shapes are examined using CFD software SHIPFLOW. The hull form is modal tested. The propeller geometry is optimized for the given engine and a suitable gear box. The proposed design is then investigated for its manoeuvring ability in shallow waters. The hydrodynamic sway forces yaw moments and nominal wake distribution for port and starboard propellers during manoeuvring motion are estimated by CFD software SHIPFLOW. The barge’s directional stability performance is investigated for twin-propeller twin –rudder configuration.