Hydrodynamic Coefficients of a Floating Body over a Trenched Channel

Article type: Research Article

Authors: Demirel, Vedat | Wang, Shen

Affiliations: Div. of Appl. Marine Phys., Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida, U.S.A.

Abstract: Navigation of large ships over a dredged channel often experiences some unusual movements which do not commonly occur in an otherwise unrestricted waters. In particular, these distinctive and abrupt movements are more noticeable in the horizontal motions than in the vertical motions. This phenomenon, long been experienced by pilots navigating over dredged waterways, is indeed a hydrodynamic response of wave trapping inside the channel. For some particular matching of ship beam with the channel bank clearance, at some critical depth of the overbank, a ship may experience an unusual sharp increase or decrease of hydrodynamic pressure over the ship hull. This paper investigates the two-dimensional nature of this phenomenon. The problem for a two-dimensional body of arbitrary cross section oscillating on the free surface of a trenched channel is formulated and solved by a numerical boundary element technique. Results of the added mass and damping coefficients for a rectangular form hull are presented. The effects of the relative dimensions between the ship's beam, draft and the trench width, depth as well as the channel overbank depth are examined.

DOI: 10.3233/ISP-1990-3741005

Journal: International Shipbuilding Progress, vol. 37, no. 410, pp. 199-215, 1990