Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The effect of directionality on extreme wave design criteria
AU - Jonathan, P.
AU - Ewans, K.
PY - 2007
Y1 - 2007
N2 - Sea state design criteria for offshore facilities are frequently provided by direction. For example, it is typical for return-period values of the significant wave height to be specified for each of eight 45° sectors in addition to the omni-directional case. However, it is important that these criteria be consistent so that the probability of exceedance of a given wave height from any direction derived from the directional values is the same as for the omni-directional value. As recently demonstrated by Forristall it is not sufficient simply to scale the directional values so that the value of the wave height from the most severe sector is the same as the omni-directional value. We develop an approach for establishing appropriate directional criteria and an associated omni-directional criterion for a specific location. The inherent directionality of sea states is used to develop a model for the directional dependence of distributions of storm maxima. The directional model is applied to the GOMOS data, and the distributional properties of the 100-year significant wave height are estimated and the implications for design discussed. An objective risk-cost approach is proposed for optimising directional criteria, while preserving overall reliability. Simulation studies are performed, using realistic extreme value assumptions, to quantify the uncertainties. © 2007 Elsevier Ltd. All rights reserved.
AB - Sea state design criteria for offshore facilities are frequently provided by direction. For example, it is typical for return-period values of the significant wave height to be specified for each of eight 45° sectors in addition to the omni-directional case. However, it is important that these criteria be consistent so that the probability of exceedance of a given wave height from any direction derived from the directional values is the same as for the omni-directional value. As recently demonstrated by Forristall it is not sufficient simply to scale the directional values so that the value of the wave height from the most severe sector is the same as the omni-directional value. We develop an approach for establishing appropriate directional criteria and an associated omni-directional criterion for a specific location. The inherent directionality of sea states is used to develop a model for the directional dependence of distributions of storm maxima. The directional model is applied to the GOMOS data, and the distributional properties of the 100-year significant wave height are estimated and the implications for design discussed. An objective risk-cost approach is proposed for optimising directional criteria, while preserving overall reliability. Simulation studies are performed, using realistic extreme value assumptions, to quantify the uncertainties. © 2007 Elsevier Ltd. All rights reserved.
KW - Design
KW - Extreme
KW - Gulf of Mexico
KW - Hurricane
KW - Risk
KW - Wave direction
KW - Wave height
KW - Extreme wave design crieria
KW - Offshore facilities
KW - Computer simulation
KW - Mathematical models
KW - Probability
KW - Reliability theory
KW - Seawater
KW - Water waves
KW - sea state
KW - significant wave height
KW - storm surge
KW - wave direction
KW - wave modeling
KW - Atlantic Ocean
U2 - 10.1016/j.oceaneng.2007.03.003
DO - 10.1016/j.oceaneng.2007.03.003
M3 - Journal article
VL - 34
SP - 1977
EP - 1994
JO - Ocean Engineering
JF - Ocean Engineering
SN - 0029-8018
IS - 14-15
ER -