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Flow Around Ships Sailing in Shallow Water - Experimental and Numerical Results
Pages 968-982

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From page 968... ... , c RANSEsolver using c fictitious compel bility md Thus c flux-dffference- plitting technique md c pole ticl theoretic medhod devised for The h mscritical regime Isolnons'l, where the hull is described merely by its cross-sectiomnl area INTRODUCTION In 6 is paper The sp cial characteristics of the flow ar md ships sailing m shallow water me demonshated for two hull forms hough These is no w 11 defined limit for the water depth h dividing shallow from deep water, the behaviour of waves is w 11 k wn to depend on the depth h he behc iour of vessels scilmg m shallow water may be charateri:D:d by one cinematiccl parameter, the dimensionless n mber For,, th depth Frond m mber, defined es: F.,, = with V the speed of the ship md g The g avitatiomnl acelemtion Fnr, clearly rules The wave resist mce of the ship, by representing The ratio of V to the so celled critical velocity ,/: leading thus to c division of the whole velocity r mge into c subcritical md c supercriticcl legion dep riding on Fnr, being smaller or larger thm 1, in similarity with what happens et high velocities m Hi, where the velocity of so md is The critical velocity, separctmg The mbsonic fiom the supersonic r mge he velocity r mge of V with values of 0 9 < Fnr, < I I is termed The h mscriticcl r mge So the rather pronounced ch mge m The mug itude of The wave resist mce is characterized by c single m mber, while the situation for the viscous resi tance is different, as There is no critical velocity md Therefore no n mber similar to Fnn From values of Fnr, ~ 0 65 The wave resi tance mcreses steeply for increai g velocity V becoming higher 6 m The wave resist mce on deep water et the same velocity he wave resist mce hr. c Icccl maxim m in the h mscriticcl region ash re nl6honfh The peed of the ship being kept con t mt, no rend flow me may be attained, while so celled solitons detach from The hull mming ahead of The ship ff the vessel is forced mto the supemriticcl r mge, the wave resistance becomes low r 6 m The one which would be obtained et The same speed m deep water A other key parameter for The i fluency of the water depth on the resistance is The depth to d aft ratio h T Read the entire page →
From page 969... ... The two selected examples of ship t pes are typical for the irme tigative pe formance of She VBD m both fields FD md CFD h both cases the emphasis is on She sailing on shallow water, md as the topic h re is flow aro Ed She ship, no allusion will be made to h im, smkage or resistmce values obtzired MODELS INVESTIGATED Shallow river vessel The model investigated Fig 1) is z typical inkmd wate way ship for extreme shallow water The stern is, as cm be en from the lines plm, desigmed to allow She installation of z sp cial flat f uster system (Schottel P mp Jet) Read the entire page →
From page 970... ... T is is 6 finite vol me method using 6 tructmed g id Inhoducmg 6m 6 tifici~l compressibility 6 coupling of the so obt~ined contmnity equation to the moment m equations is 6chieved, 611cwmg 6m efficient Roe flux-dffference- plitting techmique Th method mcludes 6he comput~tion of the fre water surf6 conside~ed 6s 6he bo md6 y betw en water 6md 6 ir 6md descobed by 6 so ca 11ed level set f mction satisfymg 6m 6dditiomd equation (derived fr m th bo md6 y condition) solved togedher with the 6bove mentioned equations The turbulence model is the tamd6 d k-8 model (St mt, 1999) Read the entire page →
From page 971... ... Experi mental results at A) Read the entire page →
From page 972... ... at h/T= 2.0, Fn = 0.098, Fnh = 0.512, Rn = 4.94* 106 The colour of the velocity vectors of the computational results for Ship A indicates the absolute value of the velocities, with warm for high and cold for low speed. Read the entire page →
From page 973... ... Experi mental results at h/T = 2.0, Fn = 0 098, Fnh = 0 512' Rn = 4.94* Read the entire page →
From page 974... ... extended in xdirection from 1.5 Lpp in front to 0.5 Lpp behind the ship, from the water plane to the bottom and from the center plane to a channel width of 4.9 m (half breadth of the VBD towing tank) Read the entire page →
From page 975... ... Fig.29:W~ersurF>edd~nnation (. Expc~imontsl~esults at ~/F = 1.3, ~=0.138, Ash ~ 0.685, An = 1.19* Read the entire page →
From page 976... ... . Experimental results (5-hole-pressure probe) Read the entire page →
From page 977... ... Experimental results (5-hole-pressure probe) Read the entire page →
From page 978... ... Computational results (Method 3) Read the entire page →
From page 979... ... and computed (dashed line, Method 4) wave cuts for different y/h at h/T= 1.5, Fn = 0.1406, Fnh = 0.6302, Rn = 1.097* Read the entire page →
From page 980... ... For Ship B in addition the experimental values as shown by the color distribution are misleading, as pressure taps were not located precisely on the sharp edges bordering the tunnels but on the sides of these edges avoiding thus likely cusps in the real pressure distribution, the interpolating postprocessing routine producing rather a smoothed distribution. Advancing to the distribution of the velocity as a vector field we are nevertheless faced with a better correspondence. Read the entire page →
From page 981... ... 7th International Conference on Numerical Ship Hydrodynamics, Nantes Grotians and Menter (1998~: Wall Functions for General Application CFD Codes, ECCOMAS 98, Fourth European Computational Fluid Dynamics Conference, Athen N.N. (1999~: Using CFX-S for Unix & Windows NT User manual from AEA Technologies, Harwell, UK Read the entire page →
From page 982... ... Ku contobuted by thei guid mce m fhe preparation md formu ztion of fhis conh~bution 7hmks go to fhe mstitutions from fhe tate Nor d h in-We sffzlen md fhe Fe deral R public Germ my which fumded the research projects involved REFERENCES Chea, X.-N. Read the entire page →

From page 968...

... , c RANSEsolver using c fictitious compel bility md Thus c flux-dffference- plitting technique md c pole ticl theoretic medhod devised for The h mscritical regime Isolnons'l, where the hull is described merely by its cross-sectiomnl area INTRODUCTION In 6 is paper The sp cial characteristics of the flow ar md ships sailing m shallow water me demonshated for two hull forms hough These is no w 11 defined limit for the water depth h dividing shallow from deep water, the behaviour of waves is w 11 k wn to depend on the depth h he behc iour of vessels scilmg m shallow water may be charateri:D:d by one cinematiccl parameter, the dimensionless n mber For,, th depth Frond m mber, defined es: F.,, = with V the speed of the ship md g The g avitatiomnl acelemtion Fnr, clearly rules The wave resist mce of the ship, by representing The ratio of V to the so celled critical velocity ,/: leading thus to c division of the whole velocity r mge into c subcritical md c supercriticcl legion dep riding on Fnr, being smaller or larger thm 1, in similarity with what happens et high velocities m Hi, where the velocity of so md is The critical velocity, separctmg The mbsonic fiom the supersonic r mge he velocity r mge of V with values of 0 9 < Fnr, < I I is termed The h mscriticcl r mge So the rather pronounced ch mge m The mug itude of The wave resist mce is characterized by c single m mber, while the situation for the viscous resi tance is different, as There is no critical velocity md Therefore no n mber similar to Fnn From values of Fnr, ~ 0 65 The wave resi tance mcreses steeply for increai g velocity V becoming higher 6 m The wave resist mce on deep water et the same velocity he wave resist mce hr. c Icccl maxim m in the h mscriticcl region ash re nl6honfh The peed of the ship being kept con t mt, no rend flow me may be attained, while so celled solitons detach from The hull mming ahead of The ship ff the vessel is forced mto the supemriticcl r mge, the wave resistance becomes low r 6 m The one which would be obtained et The same speed m deep water A other key parameter for The i fluency of the water depth on the resistance is The depth to d aft ratio h T

Flow Around Ships Sailing in Shallow Water - Experimental and Numerical Results Pages 968-982

Flow Around Ships Sailing in Shallow Water - Experimental and Numerical Results
Pages 968-982