In-Situ Turbulent Boundary Layer Measurements Over Freshly Cleaned Ship-Hull Under Steady Cruising

Nugroho, B. and Baidya, R. and Nurrohman, M.N. and Yusim, A.K. and Prasetyo, F.A. and Yusuf, M. and Suastika, I.K. and Utama, I.K.A.P. and Monty, J.P. and Hutchins, N. and Ganapathisubramani, B. (2017) In-Situ Turbulent Boundary Layer Measurements Over Freshly Cleaned Ship-Hull Under Steady Cruising. In: International Conference on Ship and Offshore Technology, 14 - 15 Desember 2017, Jakarta, Indonesia.

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Abstract

A novel study on assessing the drag penalty due to hull roughness from a recently cleaned and painted ship hull is reported. Here we estimate the rough surface drag penalty by measuring the velocity profile directly over the hull of an operating ship under steady cruising using a Laser Doppler Anemometer (LDA). The novel technique is non-intrusive and requires only optical accessand does not require a full hull-penetration. For this experiment a small glass window is placed on the double-bottom hull of an operating ship, allowing the LDA to measure the velocity gradient in the turbulent boundary layer formed over the hull (during steady sailing) across some traversable distance from close to the hull surface, to at least the end of the logarithmic region. Preliminary initial results show that there is an approximate 37% increase in skin-friction drag for a recently cleaned ship-hull compared to the hydrodynamically smooth surface

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: hull roughness, velocity gradient, hull surface
Subjects: V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture)
Divisions: Faculty of Marine Technology (MARTECH) > Ocean Engineering
Depositing User: - Davi Wah
Date Deposited: 02 Aug 2019 08:10
Last Modified: 02 Aug 2019 08:10
URI: http://repository.its.ac.id/id/eprint/69416

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