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Numerical Appraisal of the New Slender Ship Formulation in Steady Motion
Pages 239-258

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From page 239... ... It is disclosed that it is not possible to represent the slender ship floating on the free surface by the source distribution along the longitudinal axis considered in the free surface. The boundary value problem is expressed by an integral equation on the hull surface, because the singularity representing the hull must be distributed over the surface. Read the entire page →
From page 240... ... Items of the numerical work are the pressure distribution on the hull surface, wave resistance, the lateral force when moving obliquely, the wave profile alongside the hull, and the wave pattern around the hull. Some of the numerical results are compared with measured data. Read the entire page →
From page 241... ... Thus the fluid motion around the hull is expressed by the distribution of Kelvin-sources over the hull surface. The Kelvin-source is given by the formula, G(P,Q) Read the entire page →
From page 242... ... Therefore the function 0'~x,y,z) is given by 2Ko 2 loos z-KOseC2 S intz see d \| Liz+ K ~ sect ~ x e-t~xcosO+ysinO~dt -4Kof~ e~KOSec ~Zsin(KOxsecO) Read the entire page →
From page 243... ... , the ~irect~on cosine of the normal can be written as axe -fX/i: -- fz = VX nay +1/~ = v nor -fz/ ~ = v Then the hull surface condition is expressed as a;; ~ it;= -Unix where 3/3v = vy3/Dy + v 3/3z. Taking the representation ~ = �1+ $2 we can write 3$l 3~2 - = -us - ~ When the ship is placed obliquely to the uniform flow, with a drift angle A, the boundary condition on the hull surface becomes (43) Read the entire page →
From page 244... ... Substituting the expression for ~ in f50;, the pressure distribution is determined. The free surface elevation, forces and moment are calculated therefrom. Read the entire page →
From page 245... ... This fact suggests the inadequacy of the original form of the slender ship theory, which employs the double body potential as the near field solution. Fig.4 shows the pressure distribution on the hull surface at Froude number 0.267. Read the entire page →
From page 246... ... Fig. 4 Pressure distribution on the hull surface at F= 0.267 n .n's ~=~-~_~`Q3363~\ 1' .P. Read the entire page →
From page 247... ... Fig.9 shows the computed wave profile alongside the model at ~ =10�, Froude number 0.267. The result of measurement with 2m-model at Yokohama National University is also shown. Read the entire page →
From page 248... ... 11 Measured wave pattern ~= 10�, Fn=0.267 /~ 0.0( ~' ~1 1 '0 50 10� a ls� 20� 248 `~,,~ Fig. 13 Computed Lateral force coeffi ci ent Read the entire page →
From page 249... ... A remarkable effect of the vertical keel to the source distribution on the canoe body at finite drift angle is observed. Fig.18 gives the wave profile alongside the hull, and Fig.19 illustrates the wave pattern around the hull by the wave contour, at the drift angle 0�, 4�, 8�, at Froude number 0.269. Read the entire page →
From page 250... ... Towing test results are given by the total resistance coefficient CT, the residual resistance coefficient CR based on the Schoenherr friction coefficient, and the wave resistance coefficient derived by the assumption of the form factor K = 0.29. The curve of residual resistance fits the computed values approximately. Read the entire page →
From page 251... ... 269 lr I I I Fi 9. 1 9-b Computed wave contour with keel Fn= 0.269 251 Read the entire page →
From page 252... ... c, 1 n 252 /CI / CR , / ///cH / // ~ ~ /,/ Fig. 21 Computed wave resistance coefficient compared with test results of yacht model with keel Cxxlo3 4.0 _ 3.O _ 2.0 _ CX= ~ Fn =0 .359 nEAsuRED BT n I TSU I (UITI.I KEEL ~ RUDDER) Read the entire page →
From page 254... ... Similarity between computed and measured wave patterns is observed. In Fig.34, the computed wave resistance coefficient is compared with the residual resistance coefficient based on the Schoenherr friction coefficient and the wave pattern resistance by the longitudinal cut method. Read the entire page →
From page 255... ... CONCLUSIONS The validity of the new slender ship formulation is examined by the computation of the wave pattern and wave resistance of the Wigley hull, the sailing yacht hull and the Series 60 model. Satisfactory agreement is obtained in pressure distribution on the hull surface, the wave profile alongside the hull, and the wave resistance, between computed and measured values with respect to the Wigley hull. Read the entire page →
From page 256... ... Japan No.209 (1988) 13.i Song, W.-S., "Wave-making Hydrodynamic Forces Acting on a Ship with Drift Angle and Wave Pattern in her Neighborhood." Journ. Read the entire page →
From page 257... ... It may be important to find the approximate range for ~ in which the slender ship theory is valid. AUTHORS' REPI,Y The example for the Wigley hull in finite drift angle is rather an academic aspect because the leading edge separation must be present by the form with a sharp edge, though the theory does not take account of it. Read the entire page →

From page 239...

... It is disclosed that it is not possible to represent the slender ship floating on the free surface by the source distribution along the longitudinal axis considered in the free surface. The boundary value problem is expressed by an integral equation on the hull surface, because the singularity representing the hull must be distributed over the surface.

Numerical Appraisal of the New Slender Ship Formulation in Steady Motion Pages 239-258

Numerical Appraisal of the New Slender Ship Formulation in Steady Motion
Pages 239-258