Energy Conservation Method Combining Anti spray Rail and Wedge Flap for High speed Displacement Hulls

Lijo Joseph; Naga Venkata Rakesh N; V Anantha Subramanian

doi:10.14429/dsj.69.12893

Lijo Joseph Department of Ocean Engineering, IIT Madras, Chennai - 600 036
Naga Venkata Rakesh N Department of Ocean Engineering, IIT Madras, Chennai - 600 036
V Anantha Subramanian Department of Ocean Engineering, IIT Madras, Chennai - 600 036

DOI: https://doi.org/10.14429/dsj.69.12893

Keywords: Integrated wedge flap, Anti-spray rail, Dynamic trim, Energy saving device

Abstract

The hydrodynamic mechanism and parametric influences of the wedge flap and the anti-spray rail in combination is investigates. A methodology with specific guidelines for incorporating these appendages with significant drag reduction is provided. Small crafts designs frequently require interventional changes to realise the desired guaranteed speed with their installed engine power. The appendages namely, the wedge, flap and anti-spray rails are used as retrofit measures or adapted in new hull forms, in isolation or in combination, to improve the drag and bring down the power requirement. A judicious combination of different appendages can result in significantly reduced drag and therefore power saving. The methodology combines the results of numerical and experimental investigations. The systematic study identifies the parameters for control namely, wedge flap size in terms of the chord length, its orientation vide the angle of the wedge flap, and the anti-spray rail location with respect to the water surface. The choice of the size of the wedge flap is a constrained problem since excessive wedge flap can cause problems related to length and hydrodynamic loading. This study establishes a solution by combination of a minimum integrated wedge flap with properly located anti-spray rail to reduce the drag. The study shows favourable influences due to local pressure and numerical results using a RANSE solver show good comparison with experimental test results. The methodology is a new approach towards drag reduction in new designs as well as drag control by retrofit.

Author Biographies

Lijo Joseph, Department of Ocean Engineering, IIT Madras, Chennai - 600 036

Mr Lijo Joseph is a graduate Mechanical Engineer, currently pursuing Master of Science by research, and Project Officer at the department of Ocean Engineering, IIT Madras. His research interests are in the field of experimental and numerical ship hydrodynamics. The theme of the paper blends with his four years of work on energy conservation in high-speed displacement hulls towards higher Energy Efficiency Design Index (EEDI), highly relevant towards the green ship. He has just completed the research studies.

Naga Venkata Rakesh N, Department of Ocean Engineering, IIT Madras, Chennai - 600 036

Mr Naga Venkata Rakesh N. is currently a PhD Scholar and Project officer at the Department of Ocean Engineering, IIT Madras. He received his master’s degree in Ocean Engineering, IIT Madras in the year 2013. His research interests are in the fields of experimental and numerical hydrodynamics. PhD work is specifically focussed on hydrodynamic optimisation of wake adapted marine propellers.

He is part of the team in performing the simulations, experiments and analysis of the results for the present work.

V Anantha Subramanian, Department of Ocean Engineering, IIT Madras, Chennai - 600 036

Prof. V. Anantha Subramanian has been with the Department of Ocean Engineering, IIT Madras for the last 35 years. His major area is Naval Architecture and Ocean Engineering with specialised interest in computational fluid dynamics applications, computer-aided ship design, ship hydrodynamics, design and testing and optimisation related to ships and floating bodies. He is intensely involved in teaching, research, sponsored research projects from the industry and a successful consultant, with a large number of clients from the shipbuilding and design industry, both in India as well as abroad.

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