Research Publications

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    Holistic approach to project CWC with altair
    (Altair Technology Conference, 2015-07) Bhavaraju, Pradeep J. S.
    A Circulating Water Channel (CWC) generates a controlled flow environment and is used for various hydrodynamic research activities including flow around ships, study of fishnets, etc. The current paper utilizes various modules of ALTAIR HYPERWORKS to provide a holistic solution in completing the project i.e, modelling using SOLIDTHINKING, flow analysis across the working section of the CWC using ACUSOLVE, and developing a mechanism to generate ship motions with MOTIONSOLVE. One of the many experiments that can be conducted with the CWC is an internal tank sloshing test. A free surface flow analysis is performed for a 2D tank using RADIOSS solver validating the same with existing experimental results.
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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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    Comparative study for resistance of a bulk carrier using CFD
    (Altair Technology Conference, 2013-07) Bhavaraju, Pradeep J. S.; Revathi, Ch.; Ramesh, U. S.
    The hydrodynamic performance of a vessel depends on the shape of the hull. Therefore it is important that the hull form be carefully designed to minimize pressure distribution and resistance. A CFD analysis for the full scale bulk carrier is made to estimate the resistance at different velocitie . A 3D steady state, incompressible viscous flow analysis for 8, 12 and 14 knots at 7.8 m draft level is executed for zero offset flow angle using the CFD package ACUSOLVE and the results are compared with experimentally obtained model test results. An attempt is made to simulate free surface interaction between the bulk carrier and water using the Smooth Particle Hydrodynamics method available in RADIOSS solver.
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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.
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    Preliminary analysis for a circulating water channel using CFD
    (World Shipping Forum, 2013-02) Jaya Simha, B. Pradeep; Misra, S. C.; Gokarn, R. P.
    Sustainability in shipping includes improved designs that reduce power consumption. This requires advanced experimental techniques for hull form and propulsor development. A Circulating Water Channel (CWC) is used to generate a controlled flow environment and is used for various hydrodynamic research activities including flow around ships besides predicting its maneuvering behavior, studies for fishing nets, etc. While the experimental facilities such as towing tank facility, sea keeping and maneuvering basin are expensive, a relative low cost CWC, recognized by the ITTC community, is designed to facilitate academic and research activities and better flow studies. A preliminary Computational Fluid Dynamic analysis is carried out to minimize the variation of flow velocity through the guide vanes and across the width and study means of improving the flow uniformity in the test section of the CWC. A full scale CWC is modeled in commercially available software Altair Hyperworks 11.0 and a mesh is generated for the same. A CFD Analysis is carried out for 85°, 90°and 95° vane angles for an inlet velocity of 1.5 m/s. The results obtained are used to analyze and improve the flow uniformity in the test section of the CWC.
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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.