Random Irregular Wave
What do you know about it ?
deepLay-eks-2018-011
deepLay, August 2018
Random Irregular Wave
Wave Model
The above Irregular Wave pattern shows with single Tp ( 8s ), it explores the structure responses in a
broadband of frequencies ( period ).
Unlike Regular wave, it is single wave height in single period. Regular wave is just simple
sinusoidal wave pattern based on Hs and Hmax relation. Therefore, structure responses are
consistence at all time.
The Irregular Wave pattern is random with time, with Tp, with Gamma Factor, and it also depends
on the Seed No, which forms a different realization pattern on each Seed no.
Irregular Wave, a Random Wave
Wave Elevation, Velocity & Acceleration Time History in 3 Hrs Simulation
Seed No.
12345
901234
Max Wave Rise (m)
1.785
1.650
Max Wave Velocity (m/s)
1.220
1.189
Max Wave Acce. (m/s2)
2.301
2.587
123456
234567
345678
456789
567890
678901
789012
890123
901234
12345
1
2
3
4
5
10
20
30
40
50
100
200
300
400
500
1000
2000
3000
4000
5000
19918
51352
64477
42864
89141
82983
34067
65909
54827
48305
691571
684969
953629
796763
287641
798707
687102
644777
816749
567352
8887225
4249350
9846667
2368680
8420231
9683833
6868052
2843032
6441861
4383277
Irregular Wave, a Random Wave
Max Wave Fall Height, at Hs:1.0m with Range of Tp and Seeds No with Gamma : 1.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Irregular Wave, a Random Wave
Max Wave Rise Height, at Hs:1.0m with Range of Tp and Seeds No with Gamma : 1.0
Irregular Wave, a Random Wave
Max Wave Velocity, at Hs:1.0m with Range of Tp and Seeds No with Gamma : 1.0
Irregular Wave, a Random Wave
Max Wave Acceleration, at Hs:1.0m with Range of Tp and Seeds No with Gamma : 1.0
Irregular Wave, a Random Wave
Worst Case of Irregular Wave Dynamic analyses
The higher Wave Rise or Fall does not always give the worst result in dynamic analyses, because the
Max Wave Fall and Rise come with associate equivalent Wave Period, and period along with height
will affect the results, and period effect will be dictate by the Vessel RAOs.
90
135
45
180
0
315
225
270
Pipelay Vessel will have different characteristic motions on each Wave attacking angle to vessel
( direction ), those characteristics will determine the worst lay parameter, which depends on
Wave Height and Period.
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