The Proceedings Fifth International Conference on Numerical Ship Hydrodynamics (1990) / Chapter Skim
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Calculation of Free-Surface Flow around a Ship in Shallow Water by Rankine Source Method
Calculation of Free-Surface Flow around a Ship in Shallow Water by Rankine Source Method
Pages 643-656
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From page 643... ...
The calculated results were compared with experiments and calculations by conventional linearized analytical method. It was shown that the Rankine Source Method promises an improvement in predicting free-surface flow around a ship in shallow water than the conventional linearized analytical method.
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From page 644... ...
(F. tH and tC are represented by Rankine sources which are distributed on undisturbed free-surface SF, ship hull SH and channel surface Sc as follows : IF(P)
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From page 645... ...
5.1 Results in deep water First, calculations in deep and unrestricted water were carried out. Fig.2 shows panel arrangements for ship hull surface.
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From page 646... ...
Fig.7 shows variation of calculated wavemaking resistance for the free-surface and sea bottom panel regions in shallow water. The sea bottom panel region is larger than the free-surface region by 10% of ship length.
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From page 647... ...
OO00L' ~ ~ ~ ~ ~ ~ I I ~ I 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 En Fig.5 Comparison of wave-making resistance curves in deep water Fig.6 Arrangement of ship hull, free-surface and sea bottom panels (in/d = 2.389)
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From page 648... ...
The conventional linear calculations are less satisfactory than the present calculations. The difference of the calculated results in between 'fixed coed.' and 'free coed.' in small.
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From page 649... ...
x Conventional linear theory ,' ~ Havelock's integral ~ (6)
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From page 650... ...
Yo/~=0.1667 Aft _? ., 1 1 1 1 1 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 Fore x / ~ Aft Y Measured line on tankbottom Ship hull MU ~ —L/2 0 .
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From page 651... ...
2~/L~ ~ / ~ ~ :~-o.o_,2.SO shal low water -°° ( hid =2.389 ) Fig.13 Comparison of wave contour around a ship for different water depth (contour interval A: is 10.0)
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From page 652... ...
/ water l Conventional - Channel J linear theory ~ 1 o) / ,, ~ ~ // .,,,, // / " '4 ~ -I 0 oca 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 En 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 13 1.4 Fnh Fig.15 Comparison of wave-making resistance curves in channel 652
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From page 653... ...
Mei, C.C. and Choi, H.S., "Forces on a Slender Ship Advancing Near Critical Speed in a Shallow Channel", 4th International Conference on Numerical Ship Hydrodynamics, Washington D.C.
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From page 654... ...
In case of flat sea bottom, there is the method which takes into account infinite image of the sources distributed on the freesurface and ship hull surface. However this method can not apply to non-horizontal sea bottom generally and has much time for calculation of the infinite image.
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From page 655... ...
and Wehausen, J.V.: Ships in Very Shallow Water, Festkolloquium zur Emeritierung von Karl Wieghardt, Institut fur Schiffbau der Universitat Hamburg, Bericht Nr.427, pp.29-49, 1982.
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