scholarly journals THE EFFECT OF WAVE DIRECTION ON SHIP MOTIONS IN A HARBOUR ENTRANCE CHANNEL - MODEL STUDY APPROACH

1984 ◽  
Vol 1 (19) ◽  
pp. 217
Author(s):  
A.C. Van Wyk ◽  
J.A. Zwamborn
Keyword(s):  
Channel Model ◽  
Basic Knowledge ◽  
Scale Model ◽  
Ship Motions ◽  
Wave Direction ◽  
Extreme Wave ◽  
Essential Requirement ◽  
Study Approach ◽  
Model Study ◽  
Bulk Carriers

Basic knowledge of a ship's vertical motions in waves of different angles of approach is an essential requirement in the formulation of allowance criteria on which to base harbour accessibility under extreme wave conditions. A comprehensive series of scale model tests are being undertaken to establish minimum underkeel clearance for given channel depths and sea states using two models representing typical 150 000 and 270 000 dwt bulk carriers.

scholarly journals EXTREME WAVE PRESSURES AND LOADS ON A PILE-SUPPORTED WHARF DECK - INFLUENCES OF AIR GAP AND WAVE DIRECTION

2018 ◽  
pp. 5
Author(s):  
Andrew Cornett
Keyword(s):  
Offshore Structures ◽  
Model Tests ◽  
Scale Model ◽  
Extreme Waves ◽  
Wave Direction ◽  
Coastal Structures ◽  
Extreme Wave ◽  
Wave Impact ◽  
The Past ◽  
Water Depths

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.

scholarly journals WAVE-INDUCED SHIP MOTIONS IN HARBOUR APPROACH CHANNELS

1988 ◽  
Vol 1 (21) ◽  
pp. 216 ◽  
Author(s):  
A.C. Van Wyk ◽  
J.A. Zwamborn
Keyword(s):  
Model Simulation ◽  
Scale Model ◽  
Ship Motions ◽  
Large Bulk ◽  
Bulk Carriers ◽  
Optimum Depth ◽  
Wave Induced

The results of scale-model simulation of wave-induced hull motions of large bulk carriers under conditions representative of those for coastal ports are presented and discussed to illustrate their usefulness in studies aimed at evaluating the optimum depth requirements for port approach channels.

scholarly journals A Scale Model Study of the Bosomtwe Crater.

1965 ◽  
Vol 70 ◽  
pp. 324
Author(s):  
G. H. S. Jones ◽  
C. H. H. Diehl
Keyword(s):  
Scale Model ◽  
Model Study

Reduced-scale model study on cable heat dissipation and airflow distribution of power cabins

2019 ◽  
Vol 160 ◽  
pp. 114068 ◽  
Author(s):  
Jiaxu Wang ◽  
Xuefeng Liu ◽  
Siwei Chen ◽  
Hanghang Jiang ◽  
Guanyu Fang ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Scale Model ◽  
Model Study ◽  
Airflow Distribution ◽  
Distribution Of Power ◽  
Reduced Scale

Acoustical scale model study of the attenuation of sound by wide barriers

1977 ◽  
Vol 62 (3) ◽  
pp. 601-606 ◽  
Author(s):  
Elizabeth S. Ivey ◽  
G. A. Russell
Keyword(s):  
Scale Model ◽  
Model Study

Crane Ship Response to Wave Groups

1991 ◽  
Vol 113 (3) ◽  
pp. 211-218 ◽  
Author(s):  
T. E. Schellin ◽  
T. Jiang ◽  
S. D. Sharma
Keyword(s):  
Continuous Wave ◽  
Amplitude Spectrum ◽  
Large Angle ◽  
Second Order ◽  
Scale Model ◽  
Ship Motions ◽  
Nonlinear Simulation ◽  
Wave Groups ◽  
First Order ◽  
Load Response

The motion response of a shear-leg crane ship lifting a heavy load in wave groups was investigated. The 9-DOF dynamic model incorporated hull motions coupled with nonlinear large-angle load swing and elastic stretch of the hoisting rope assembly. Hydrodynamic response forces and wave excitation forces were taken to be frequency dependent, and nonlinear mooring system restoring forces were allowed for. Closed-form linearized results about the system equilibrium state verified our nonlinear simulation algorithm; simulation results in comparison with scale model test measurements, our mathematical model. Wave groups were idealized in two different ways: 1) as continuous wave groups produced by pairs of beating waves of equal amplitude and slightly different periods, and 2) as isolated wave packets generated by superimposing a large number of regular wave components derived from a Gauss-modulated amplitude spectrum. Simulations show that hook load response, strongly coupled with ship motions, was mainly influenced by first-order wave-exciting forces. Low-frequency horizontal ship motions caused by second-order wave (drift) forces did not generally affect hook load response, i.e., first-order and second-order responses were independent.

An Experimental Investigation of Roll Motions of an FPSO

2008 ◽  
Author(s):  
Paulo T. T. Esperanc¸a ◽  
Joel S. Sales ◽  
Stergios Liapis ◽  
Joa˜o Paulo J. Matsuura ◽  
Wes Schott
Keyword(s):  
Degrees Of Freedom ◽  
Wind Waves ◽  
Scale Model ◽  
Ship Motions ◽  
Random Waves ◽  
Six Degrees Of Freedom ◽  
Campos Basin ◽  
Waves And Currents ◽  
Offshore Development ◽  
Bilge Keel

FPSO roll motions can be major contributor to riser fatigue. This is especially true in regions where wind, waves and currents are non-collinear. Roll motions as high as 23 degrees have been reported in the Campos Basin. The most common roll mitigation strategy consists of adding bilge keels to the FPSO. Motivation for this work came from a need to develop a better understanding of roll motions as a function of bilge keel width. In addition to roll motions, the hydrodynamic forces on the bilge keels were measured. A series of tests were conducted at the LabOceano offshore basin. This new facility has a length of 4 0 m, a width of 30 m, a depth of 15 m and is equipped with a multi-flap wave generator on one side. A ship-shaped FPSO design with sponsons for a deepwater offshore development in Brazil was tested. It has a length of 316 m, a breadth of 57.2 m and a draft of 28.3 m. A 1:70 scale model was constructed. A horizontal soft mooring system consisting of four lines with springs was used. Regular waves of different amplitudes as well as random waves were generated in the basin. Two different loading conditions, ballast (draft = 6.7 m) and loaded (draft = 21.7 m), as well as three wave headings, beam seas (90°), and quartering seas (22.5°, 45°) were considered. Tests were undertaken for four bilge keel configurations, corresponding to a case without bilge keels, as well as bilge keels of 3 different widths (1 m, 2 m and 3 m). In all cases, the bilge keels had a length of 200 m. An optical system was used to measure ship motions in all six degrees of freedom. The hydrodynamic loads on the bilge keels were measured using strain gages.

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