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Trans RINA, Vol 157, Part A3, Intl J Maritime Eng, Jul-Sep 2015


decreases. An increasing density of the contour lines of the surface elevation indicate a very steep wave and wave breaking is likely to occur, though not in the simulations due to the chosen mesh density. The main features of the wave- pattern agree with those presented by other researchers [15].


Fr = 0.25


Figure 10 examines the free surface elevation for medium displacement at Fr = 0.41 for ship length of L = 110 – 190m. The wave height was scaled consistently with respect to ship length and black and white indicate absolute elevations of 1% of the ship length. Whilst the characteristic features of the wave


pattern remain


unchanged as slenderness increases the wave elevation as well as the rooster tail reduces.


L = 110 m Fr = 0.29


L = 130 m Fr = 0.33


L = 150 m Fr = 0.37


L = 170 m Fr = 0.41


L = 190 m Fr = 0.45


Fr = 0.49


Figure 10: Wave elevation of large medium-speed catamarans at Fr = 0.41 of 110 – 190 m in length at medium displacement (top to bottom).


Figure 9: Free surface elevation of 130 m medium-speed catamaran at medium displacement for Fr = 0.25, 0.29, 0.33, 0.37, 0.41, 0.45, and 0.49 from top to bottom.


©2015: The Royal Institution of Naval Architects


Finally, the influence of the displacement is shown in Figure 11 for L = 130m at Fr = 0.41. Again the main features of the wave pattern remain constant, but the wave elevation, as well as the rooster tail, increase in magnitude with increasing displacement.


A-167


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