The WAG Squall Measurement System

Jeans, Gus; Redford, Stephen; Bellamy, Ian; Mundy, Richard

doi:10.1115/omae2008-57337

Cited by 4 publications

(2 citation statements)

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“…The schematic of the synthetic wind squall timeseries and the definition of the parameters are presented in Figure 7. In this simplification, it is assumed that the wind speed rises linearly in time till the peak point and then decays exponentially as (2) It has been observed that the peak 1-min averaged wind speed is a reasonable estimate for the peak speed . The rising time , and decaying half-time are estimated from the original squall timeseries.…”

Section: Synthetic Wind Squall Timeseriesmentioning

confidence: 99%

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Response of FPSO Systems to Squalls

Duggal¹,

Heyl²,

Izadparast³

et al. 2011

Volume 3: Materials Technology; Jan Vugts Symposium on Design Methodology of Offshore Structures; Jo Pinkster Symposium on Seco

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Squalls are mesoscale sudden wind-speed increases that can occur worldwide and are a design driver for FPSO systems in areas the other design environmental conditions are relatively benign, e.g. offshore West Africa. Squalls are transient winds which rapidly reach a peak wind speed (up to 50 m/s) and then decay to low speeds in a span of 60 to 90 minutes. As squalls are transient phenomena traditional steady-state analysis techniques cannot be used for the global analysis or the development of the extreme response estimates. This paper focuses on the characterization of the squall environment and the impact of various parameters on the response of FPSOs. The responses of both spread and turret moored FPSOs are presented and the difference in response is discussed. The paper then focuses on a parametric study on a representative single degree of freedom model of a spread-moored FPSO with an emphasis on the estimation of the extreme response and its dependence on sample size.

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Section: Synthetic Wind Squall Timeseriesmentioning

confidence: 99%

“…The West Africa Gust Joint Industry Project (WAG JIP) [1,2] was developed to collect measurements of squall time histories at various locations offshore West Africa and analyze the data. The database was used to estimate the extreme value distributions and consequently to predict the 100-year peak one minute mean wind speed.…”

Section: Introductionmentioning

confidence: 99%

Response of FPSO Systems to Squalls

Duggal¹,

Heyl²,

Izadparast³

et al. 2011

Volume 3: Materials Technology; Jan Vugts Symposium on Design Methodology of Offshore Structures; Jo Pinkster Symposium on Seco

View full text Add to dashboard Cite

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Squalls in sea off coast of Japan and their effects on marine operations based on weather observatory data at remote islands

Ozaki

Wada

2017

J Mar Sci Technol

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Squall Wind Elevation/Gust Factors and Squall Coherence

Santala

Calverley

Taws

et al. 2014

Day 3 Wed, May 07, 2014

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A squall is a strong transient wind event generated by a convective storm. Though squalls are an operational concern over a wide range of latitudes, they are typically only design events in tropical areas. At this time, there are no widely accepted elevation and gust factors for squalls that are appropriate for engineering purposes. No specific guidance is given on squall gusts in the present API or ISO standards. The nature of wind squall events is fundamentally different than that of high latitude non-cyclonic storms and tropical cyclones which are presently the only types of wind events specifically addressed by API and ISO standards. Such factors are needed for squall events so that measurements made in different ways may be converted into homogeneous databases at specified elevations and gust intervals such that they can be analyzed in an unbiased way. Such factors are also needed to convert squall criteria values at a specified elevation or gust interval to a relevant elevation and interval required for the engineering of a specific structure or appurtenance. The West Africa Gust (WAG) joint industry project JIP was formed to better understand the nature of wind squall extremes offshore West Africa. The WAG JIP has concluded its third and final planned phase. The first phase of WAG focused on developing regional return period extreme value estimates of squall winds. The second and third phases of WAG focused on understanding the temporal and spatial nature of squall gusts in the context of the requirements needed for offshore engineering. Results were based on an offshore multi-anemometer array set up by the third phase of the JIP (WAG3) offshore West Africa. In this paper, expressions for wind gust elevation profile and gust factors are presented for squall winds over water. Coherence of longitudinal variations in squall winds is compared to the expressions for non-squall winds presently in API and ISO standards. The results presented herein will lead to an improved treatment of squall events for offshore engineering applications.

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The WAG Squall Measurement System

Cited by 4 publications

References 0 publications

Response of FPSO Systems to Squalls

Response of FPSO Systems to Squalls

Squalls in sea off coast of Japan and their effects on marine operations based on weather observatory data at remote islands

Squall Wind Elevation/Gust Factors and Squall Coherence

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