176
CHAPTER 5. COASTAL STRUCTURE MODELS
above parameters as a complete set of dimensionless products was given by
Hudson, et al. (1979) as
F
£a H h
- Vw Vw£a £,a
Pw
j-.
T’T’r7^ra'p/Pw'£a\Pa-PwY .
= 0
(5.2)
which is a dimensionless expression of the rubble-mound stability problem.
If we consider damage (D) to be the dependent variable, then complete
similitude of damage in a physical model will be achieved provided every one
of the remaining independent dimensionless parameters in Eqn. 5.2 is the
same in the model as in the prototype for a particular set of wave conditions.
In other words, the requirements for similitude are the following:
Pa pw / p
\Pa — pw / m
_/4A
\h J
\ A /
\ / p
\
/ m
(5-3)
(H_\ _(H\
\L )
\L )
(5-4)
/ /l \
/ /l \
WP=
(5-5)
( * )p
= (a)m
(5-6)
(5.7)
(△)P = (△).
(5-8)
Wp = Wm
(5.9)
' Vw \ = (Vw \
p
\y/gCJ m
(5-10)
Vwta\ = (Vwtg\
.p/pw ) p \p/Pw / m
(5.11)
=
\ £
\ f 1
\ca / p \^ajm
(5-12)
Pw \
/ pw \
(5.13)
where the subscripts p and m represent prototype and model, respectively.
The conditions given by Eqns. 5.3 - 5.9 will be satisfied in a geometrically undistorted model. So our first requirement is