908 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. XI. 2 



Te — Period of encounter of waves, referred to 

 a ship or other point 



T E — Thrust, effective, exerted on a ship by a 

 propulsion device, = r(l — t) 



Th — Period of heave 



To — Thrust of a propulsion device in open water 



Tp — Period of pitch 



Tjj— Period of roll 



Ts — Thrust, slope, exerted by gravity on a 

 floating body on an inclined hquid surface 



Tw — Period of a gravity wave 



tx/c, tx/l — Thickness ratio of a hydrofoil section 



to/D — Blade-thickness fraction of a screw 

 propeller 



u — Velocity, linear component of, in direction 

 of longitudinal or x-axis of a body or ship 



U, V — Velocity or speed in general; specifically, 

 velocity of the liquid U or speed of the body or 

 ship V, irrespective of units of measurement 



UAfVA, y E — Velocity or axial speed of ad- 

 vance of a propulsion device, reckoned in the 

 direction of motion of the device, = U — Uw = 

 V - V^ = U{1 - w) = F(l - w) 



Ui — Velocity, induced, at a great distance 

 astern of a finite-length hydrofoil with circulation 



Ur, Vg — Velocity or speed, resultant, of the 

 flow approaching a hydrofoil, taking account of 

 induced velocity 



Us — Relative impact or striking velocity 



Ut — Velocity or speed, tip, of the blades of a 

 propulsion device, = imD 



Uw , Vw — Velocity or speed, wake, resulting 

 from all causes acting around a body or ship, 

 reckoned in the direction of motion 



UjA — Velocity, induced, axial; the axial com- 

 ponent of the induced velocity at a selected point 

 in a propeller jet with rotation 



UiT — Velocity, induced, tangential; the tan- 

 gential component of the induced velocity at a 

 selected point in a propeller jet with rotation 



Ua> , Fco — Velocity of the liquid in the undis- 

 turbed part of a stream or at a great distance 

 from a body or ship 



C/,— Velocity, shear, in viscous flow, defined 

 by Vto/p 



Uotb or Uo — Orbital velocity of a surface 

 particle in a gravity wave 



V — Velocity, linear component of, in direction 

 of transverse or y-a.xis of a body or ship, positive 

 to starboard 



V, U — Speed or velocity in general; specifically, 



speed of the body or ship V or velocity of the 

 liquid U, irrespective of units of measurement 



V,, — Speed of ship in water of depth h 



V° (F of blade circle) — Velocity, nominal tan- 

 gential, of the blades of a paddlewheel, measured 

 at midheight of the blades for a radial wheel and 

 at the blade-trunnion circle for a feathering wheel 



Va , Ve , U A — Speed or velocity of advance of 

 a propulsion device, reckoned in the direction of 

 motion of the device, = F(l — w) = U{1 — w) 



Vi — Schlichting intermediate speed, for analysis 

 of shallow-water performance 



Vm — Speed of model, as distinguished from ship 

 speed Vs 



Vo — Speed of advance of a propulsion device 

 in open water; speed of a ship along the approach 

 path just prior to entry into a turn 



Vr , Ur — Speed or velocity, resultant, of the 

 flow approaching a hydrofoil 



Vs — Speed of ship, as distinguished from model 

 speed Vm 



V s — Velocity of sound in a medium 



Vt — Towing speed of a tug 



VsT — Speed, steady-turning 



Vw , Uw — Speed or velocity, wake, resulting 

 from all causes acting around a body or ship, 

 reckoned in the direction of motion 



F„ , C/co — Speed of the Uquid in the undis- 

 turbed part of a stream at a great distance from 

 a body or ship 



F (pronounced vol) — Volume; displacement vol- 

 ume of a body or ship; alternative symbol V(also 

 pronounced vol) 



Va — Volume, afterbody, of a ship 



¥b — Volume, bulk, as of a submerged sub- 

 marine 



Ye — Volume, entrance, of a ship 



¥p — Volume, forebody 



¥p — Volume, parallel middlebody 



Vr — Volume, run 



F/(0.10L)' or V/(0.10L)'— Fatness or (vol- 

 ume-0.1 length) ratio. This is preferred to a 

 length/volume ratio because it increases as the 

 fatness increases, the same as the displacement- 

 length quotient of D. W. Taylor. 



V/\/L — Taylor quotient T^ or speed-length 

 quotient, where F is in kt and L in ft; this is 

 dimensional 



w — Velocity, linear component of, in direction 

 of the z-axis of a ship, from deck to keel 



w— Wake fraction of Taylor, = (F - Va)/V = 

 (F - Ve)/V 



