3 hour storm duration
3 hour storm duration
(OP)
Can someone please cite the reason that a design load is based on its maximum value during 3 hours of a 100-year storm? In other words, why is the storm duration assumed to be 3 hours. Is the most intense period of a storm expected to last 3 hours, even though the synoptic time scale of storms is longer (3-5 days)? Or is 3 hours chosen because Hmax ~ 2*Hs? I would really like to see a technical explanation of the 3 hour interval. Thanks!
RE: 3 hour storm duration
RE: 3 hour storm duration
RE: 3 hour storm duration
RE: 3 hour storm duration
RE: 3 hour storm duration
"Over an interval of 3 hours the statistics do not change very much and the seastate may be described by significant wave height (Hs) and mean zero crossing period (Tz)."
RE: 3 hour storm duration
"Three hours has been introduced as a standard time between registrations of sea states when measuring waves, but the period of stationary can range from 30 minutes to 10 hours."
DNV-RP-H103 mentions 3 hours as well.
Remember the 1.86 factor which is said to be the ratio between max wave height and sig wave. I've used that for years without complaint.
So I guess the stats people think that after 3 hours you just see (statistically) a max wave height that doesn't differ much from using say a 4hour, 5hour... 10 hour etc. storm data.
RE: 3 hour storm duration
However for some analysis (e.g. Fatigue analysis), if you can prove that a time duration less than 3hrs will give results that are statistically ok compared to the 3hrs, it will be acceptable.