146
4 How to Determine Wave Parameters
Table 4.1: Some wave height relations based on the Rayleigh distribution. Adapted
from Massel (1989)
:? i:l::::;
Characteristic height
H
H
H
Hrms
0"(
Hs
Root-mean-square
height
Hrms
1.0
2v0
0.706
Median height
H(P = 1/2) (In 2)1/2 (8In2)1/2 0.588
Mean height
H =Hl
FJ2 ,;2; 0.626
Significant height
Hs = Hl /3
1.416
4.005
1.000
A verage of tenth
highest
H l / IO
1.80
5.091
1.271
A verage of hundredth
highest
H l / IOO
2.359
6.672
1.666
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Normalized wave height H / H
Fig. 4.25: Probability density distribution of wave height (H = 1.0 m)