Research Publications
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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 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.