B.l. ROMAN SYMBOLS
541
d - ordinary differential operator
d - diameter
d - sediment grain diameter
dso - median armor stone size
dso - median sediment grain size
D - drag force
D - characteristic dimension of quarrystone core material
D - percent damage to cover layer
(displaced/total armor units)
D - directional wave spreading function
Di - Fourier coefficient of the ith linear component
of horizontal velocity
Dm - relative depth of mth component
Dn - relative depth of nth component
Dp - effective prototype quarrystone diameter (in cm)
Dœ - sediment fall speed parameter (or Dean number)
£>50 - nominal median armor unit diameter
e - mathematical transcendental number [= 2.71828...]
e - boundary layer energy
e
- wave board stroke amplitude
E - modulus of elasticity
E - wave energy
E - second incomplete elliptical integral
E - smooth instantaneous wave energy history (SIWEH)
Et - energy lost by bottom viscous dissipation
Ei - a function of Fourier coefficients and time lag
Ej - total energy contained in the incident wave spectrum
LTr - total energy contained in the reflected wave spectrum
Eu - Euler number
Ew - energy lost by side wall viscous dissipation
E - time-averaged value of £?(/)
f
- function
f
- frequency
fn
~ spectrum higher frequency integration limit
/l
- spectrum lower frequency integration limit
fu
~ Nyquist frequency
f0
- frequency interval