344 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. 59.13 



stream velocity U^ at a distance, are listed in 

 Table 34. a on page 508 of Volume I for a range 

 of thrust-load factor Ctl of from 0.040 to 360.0. 

 These ratios are indicated graphically in Figs. 

 34. D and 34. E on page 510 of that volume. 



In diagram 1 of Fig. 59. G there are plotted, to 

 scale, the longitudinal jet outlines for the liquid 

 passing through an imaginary actuator disc from 

 6i2 or 3Z) ahead to QR or 3Z) abaft the disc 

 position, at varied thrust-load factors. If R is the 

 radius of the actuator. Table 59. c gives the theo- 



T.\BLE 59. c — Inflow- and Outflow-Jet Diameters 



AT %R Ahead and Astern of an Imaginary Actuator 



Disc of Radius R 



The values tabulated are entirely theoretical, for an 

 ideal liquid and no external interferences. 



Thrust-load Ideal efficiency. Inflow-jet Outflow-jet 

 factor, Ctl vi radius radius 



retical inflow and outflow jet radii for 3D ahead 

 and 3D astern, respectively, for the .seven values 

 of Ctl indicated in Fig. 59. G. These are derived 

 from the relationships 



R\nl\o, 



=e 



and 



Ro« 



R 



\2 - Vr/ 



(59.iiia) 



(oO.iiib) 



for the 6/2- or 3D-axial distance. For example, 

 from Table 34. a, for a Ctl of 6.0, the ideal effi- 

 ciency ij/ is 0.549. Then 



RlnH 



°' = ^(dig) 



1.35/2 



/2o„,.,.o.iet = ^(2 _ 0.549) = *^-^^^- 



Diagram 2 of Fig. 59. G illustrates graphically 

 the rate of variation of (?/<» -1- kUj) with axial 

 distance ahead of and abaft the actuator disc. 

 This rate is valid for any finite value of the thrust- 

 load coefficient. Diagram 3 of the figure indicates 

 a typical rate of variation of Ap with the same 

 axial distance. In this case the differential-pres- 



^^^19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36"' 



Corrected Ship Speed Throuqh the Water, kt 



Fig. 59. H Variation of Thrust-Load Coefficient with Ship Speed and Speed-Length Quotient for 



Destroyer Hamilton (DD141) 



