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CHAPTER 4. HYDRODYNAMIC MODELS
where
xp
■
Xm -
zp
Zm
Nx -
Nz -
prototype horizontal dimension
- model horizontal dimension
prototype vertical dimension
model vertical dimension
horizontal length scale
vertical length scale
and the factor “A” is now defined in terms of the horizontal lengths as
X
D
±L. = K^- or NX = KND
(4.119)
Xm
Dm
where D is the stone size.
The solid lines in Figure 4.6 are lines of constant values of the factor, A,
and the abscissa is a dimensional factor that combines several parameters
of the rubble-mound structure. This factor (similar to Eqn. 4.35) is
L>p3Pp5
(4.120)
where
Hi
NL
height of the incident wave.
- average width of the core material section,
(therefore, AHi/NL is the gradient of head
loss through the voids in the core material).
DP
effective quarrystone diameter (in centimeters)
of the prototype core material, and it is taken as 10%
smaller than quarrystone from the core material
gradation curve.
P
porosity of the core material (0 < P < 1).
It is important to note that Dp must be a prototype stone diameter in
centimeters. Also, the parameters Hi and AL must be prototype values
because they form a ratio that will not be preserved in a geometrically
distorted long-wave model.
Hudson, et al. (1979) stated that Keulegan’s (1973) method, as represented by Eqns. 4.36 - 4.40, can also be used to size model stone structures
for correct wave transmission provided Eqn. 4.119 is used to determine the
relationship between Dp and Dm.