Research Publications
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Item Numerical study on maneuvering a container ship in shallow water waves /(IJIRSS, 2023-09-15) Mallampalli, Premchand; Janardhanan, Sheeja; Karottu, KesavadevVarikattu; Ommi, GnaneswarNumerous 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.Item Shape improvisation of the solar panels on the roof of an electric vehicle /(Springer Nature, 2021-06-15) Janardhanan, SheejaIt 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.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.Item Comparitive CFD study for a ship hull with sonar dome a different positions(IIT, Kharagpur, 2011-12) Jaya Simha, B. Pradeep; Das, H. N.; Niranjan Kumar, I. N.Sonar Domes are traditionally Hull Mounted and is placed in between bow and the mid ship. Placing the dome in such a way greatly reduces the risk of damage in heavy seas but it requires extreme design consideration. However, bow mounted domes also exhibit hydrodynamic advantages and are becoming more and more popular with time. A bow mounted dome may work like a bulbous bow and helps reducing the drag of the ship. The position of the appended dome greatly influences the flow near the hull and greatly affects the performance of the hull. Since there is a scope to position the dome at various locations along the hull, a CFD analysis is done to determine the performance of hull at three different positions of the ship and the results are compared in this paper. A detailed study of flow including streamlines, drag, wake at different regimes of flow etc., is made for different configurations of the dome. The sonar dome is placed at different locations beginning from the bow end to the mid-shipsection along the center-line of the ship and the performance of the hull is studied. The surface model of the sonar dome with hull is generated using modeling package CATIA. Surface and volume mesh is generated thereafter using ICEM CFD (v 10.0). The mesh is imported for flow analysis into Fluent (v 6.2) software. RANS equation was solved for turbulent, viscous and steady flow. However, the free surface could not be resolved well with Fluent and hence wave-resistance could not be estimated with Fluent. SHIPFLOW software was used to get wave resistance. SHIPFLOW solves potential flow equations for estimating waves and predicts skin friction from boundary layer equations. The CHAPMAN solver of SHIPFLOW was also used to estimate the fully turbulent flow near the stern region. Whereas, the RANS solution of Fluent is expected to predict viscous resistance more accurately the wave resistance may be confidently predicted from potential flow solver of SHIPFLOW. Use of different flow-equations for estimating different components of ship-resistance is an interesting aspect of this paper. Finally the performances of ship hull with sonar dome at different positions are compared to obtain the best location.Item 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, SheejaIt 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.