906 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. XI. 2 



L/h — Length to hull-height ratio of a sub- 

 merged body 



m — Camber ordinates of the meanline of an 

 airfoil or hydrofoil section, reckoned from the 

 base chord 



m — Mass in general, = W/g; mass of a body 

 or ship, = A/g 



m — Metacentric height, = GM, for use in 

 mathematical formulas 



m — Strength of a source or sink, such that the 

 total volume of Uquid per unit time flowing from 

 a 2-dimensional source of unit depth is 2;rm and 

 from a 3-dimensional source is 47rm 



lUx — Camber ordinate, maximum, of the mean- 

 line of a hydrofoil or blade section, reckoned 

 from the base chord 



M — Merit factor of E. V. Telfer, described in 

 Sees. 34.10 and 60.13 



M — Moment, pitching or trimming, about the 

 y- or transverse body axis 



M„ — Mach or Cauchy number, for relating the 

 speed of a body around which flow is being 

 studied to the speed of elastic waves in the sur- 

 rounding liquid 



Mcs — Moment exerted by a control surface 

 about a principal axis of a body or ship 



TOx/c — Camber ratio of a hydrofoil 



n — Index or exponent in general 



n — Rate of angular rotation, speed, or velocity, 

 generally expressed as revolutions per unit time; 

 alternative symbol w(omega), generally expressed 

 as radians per unit time 



n — Tuning factor; ratio of natural period T of 

 ship motion to period of encounter T^ of waves 



rio — Angular rate of rotation of a propulsion 

 device in open water 



An — Streamline spacing or stream-tube width, 

 normal to the direction of liquid motion 



N — Moment, yawing, about deck-to-keel or 



— Friction coefficient of a surface in water, 

 according to R. E. Froude 



S] — Amidships in general 



S]pp — Amidships, defined as the midlength be- 

 tween perpendiculars 



^wL — Amidships, defined as the midlength on 

 waterline; alternative SJntrz, 



p — Angular velocity in roll about the x- or 

 longitudinal body axis 



p — A pressure intensity in general; any force 

 per unit area 



Pa — Pressure, atmospheric 



Pc — Pressure, bubble or cavity 



Ph — Pressure, hydrostatic 



Pi — Pressure, impact 



Po — Pressure, ambient; see also Pah and p„ 



Pp — Pressure, pumping 



Pah — Pressure, ambient, = {jpA + Ph) = sum 

 of atmospheric and hydrostatic pressures; see also 

 P- 



PAb. — Pressure, absolute 



Pco — Pressure, ambient, of the Uquid in an un- 

 disturbed stream, at a great distance from a body 

 or ship; this is an absolute pressure unless other- 

 wise indicated 



±Ap — Pressure, differential, positive or nega- 

 tive, reckoned from the ambient pressure p„ 



P — Pitch in general; pitch of a propulsion 

 device 



P — Power in general 



P„ — Planing number, = Dt/Ld 



Pb — Power, brake 



Pe — Power, effective or towrope, = RV 



Pf — Power, friction 



Pi — Power, indicated 



Pp — Power, propeller, = 2xQn; formerly known 

 as deUvered power 



Ps — Power, shaft, = 2irQn plus shaft friction 

 power 



Pj.— Power, thrust, = TV a = TVs 



Pef — Pitch, effective, when exerting zero net 

 thrust 



P/D — Pitch ratio of a propulsion device 



q — Angular velocity in pitch about the y- or 

 transverse body axis 



q — Dynamic pressure at a stagnation point Q; 

 ram pressure, expressed by (0.5pf7^) or (O.SpV^) 



Q — Quantity rate of flow of a liquid, in terms 

 of volume per unit time, where Q = V/t; output 

 of a source or input of a sink 



Q — Torque, specifically, torque applied at a pro- 

 pulsion device 



Qo — Torque of a propulsion device in open 

 water 



Qs — Spindle moment or torque, on a con- 

 trollable propeller 



Qcs — Control-surface hinge or stock torque, 

 exerted about the stock axis 



r — Angular velocity in swing or yaw about the 

 deck-to-keel or 2-axis 



