904 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. X1.2 



e — Vapor pressure of water 



E — Energy; work 



E„ — Euler number or pressure coefficient = 



p/q = (p - p»)/5 = Ap/9 



/ — Camber of an airfoil or hydrofoil (6th 

 ICSTS symbol); also m for meanline camber 



/ — Frequency; eddy frequency in a vortex 

 street or trail 



/ — Friction coefficient of a surface in water, 

 according to W. Froude, in the equation 

 Rf = fSV"; this is dimensional 



/ — A function 



/ — Ordinates, back and face, of an airfoil or 

 hydrofoil 



/ — Ratio of the section area at an end perpen- 

 dicular to the section area at midlength. This is 

 D. W. Taylor's "/" [S and P, 1943, p. 65]. 



fs — Ratio of the section area A at the FP to 

 the section area Am sit midlength 



fo — A function applying to a group of geo- 

 metrically similar bodies or ships 



/b — Ratio of the section area A at the AP to 

 the section area A^ at midlength. The ratio 

 Au/Ait is equal to /r only if the immersed 

 transom Hes at the AP. 



F — Force in general 



F — Freeboard 



F„ — Froude number; in general, = U/ 'VgL = 



Ft — 6-Froude number; specifically, the beam 

 Froude number of a planing craft = V/ 'VgB = 



F,, — Submergence-Froude number, where h is 

 the depth of submergence, = IJ I'wgh = V I's/gh 



Ft, — Blade-disc force of a screw propeller, 

 exerted tangentially in the plane of the disc at 

 the radius R of the CP of any given blade, so that 

 Q = FJi for that blade 



F D — Damping force 



Fi — Inertia force 



Fy — ^-Froude number; specifically, the volume 

 Froude number, 



g — Acceleration due to gravity = w/p 

 G — Girth, linear, measured generally from the 

 DWL 



h — Depth in general; depth of submergence of 

 a body or ship, such as a submarine 



h — Head, hydrostatic, hydraulic, or potential; 

 height or depth of liquid 



hp — Head, pressure, due to pumping, = pe/w, 

 as distinguished from head due to gravity 



hr — Head, total, including hydrostatic h, 

 pumping hp , and velocity hu ; the same as the 

 Head, total, Bernoulli, sjonbol H 



hu — Head, velocity, = U^/(2g) 



hv — Head, vapor, of a liquid 



hw — Height of a wave from trough to crest 



ha> — Head of liquid in an undisturbed stream 

 of infinite extent 



A (pronounced hull height) — Hull height of a 

 submerged body or submarine, top to bottom, or 

 deck to keel 



hw/Lw — Steepness ratio of a wave 



77— Head, total, Bernoulli, = [Uy{2g)] + 

 p/w + h; the same as the Head, total, sjrmbol hr 



H — Draft of a floating body or ship; alternative 

 symbols d and T 



H — Shape factor of a boundary-layer velocity 

 profile, = d*/d, where 6 is momentum thickness 



H^ — Draft, aft; generally measured at the after 

 perpendicular 



Hd — Drag, keel, as a vertical distance, repre- 

 senting a difference in drafts at the forward and 

 after perpendiculars when the keel line is extended 

 to those perpendiculars 



He — Draft, extreme, wherever occurring along 

 the length 



Hp — Draft, forward; generally measured at the 

 forward perpendicular 



Hm — Draft, mean, at midlength 



Hu — Draft, immersed transom 



Hx — Draft at section of maximum area; alter- 

 native symbols dx and Tx 



h/B — Hull-height to beam ratio of a body 



h/L — Hull-height to length ratio of a body 



Hp/L — Slope of keel, in a ship with a designed 

 drag; keel-drag ratio 



i — Slope of a line defining a form, with refer- 

 ence to a specified or selected axis or plane; may 

 be expressed as an angle in degrees or as a natural 

 tangent 



Ib — Slope, bowline or buttock, with reference 

 to baseplane 



in — Slope, diagonal, with reference to inter- 

 section of a diagonal plane and the centerplane 



Ie — Slope, waterline, in entrance, with refer- 

 ence to centerplane, neglecting local shape at the 

 stem; alternative symbol {l/2)aj! 



ip — Slope of floor (bottom of ship), with 

 reference to baseplane 



