Table 4-9. Assumptions for Pg5 Formulas in Table 4-8.
1. Formula 1 — Equation 4-35
a.
Energy density at breaking is given by linear theory,
Ê = (pgHj)/8 « 8HJ
b.
Group velocity equals wave speed at breaking, and breaking speed is given by
solitary wave theory according to the approximation. (Galvin, 1967, Equation 11.)
Cf = C « (2g H(,)* = 8.02 (Hfc)*
c.
a can be replaced by
2. Formula 2 — Equation 4-36
a.
Same as 1b above
b.
is related to Ho by refraction and shoaling coefficients, where the coefficients
are evaluated at the breaker position
Hb =
K, Ho
c.
Refraction coefficient KR given by small-amplitude theory ; shoaling coefficient
assumed constant, so that
d- (Hb)^ = 114 (cos«o)y4 Ho1/l
if (cosotjJ^ = 1.0
and (Kj*4 = 1.14
3. Formula 3 — Equation 4-37
a.
Refraction coefficient at breaking is given by small-amplitude theory.
4. Formula 4 — Equation 4-38
a. Same as la above
b. Same as 1b above
c. Same as 3a above
d. Cos
= 1.0
NOTE: Constant, enluated for foot-pound^econd unit,. Small-amplitude theory i, assumed valid in
deep water. Nearshore contour, are a.sumed to be straight and parallel to the shoreline.
4-98