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Mini-séminaire du LHEEA - 07 décembre 2017

Le Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique de Centrale Nantes (LHEEA) organise des mini-séminaires tous les jeudis midi. Rendez-vous en salle de télé-enseignement au bâtiment D les jeudis à 13h45. Allez-y, c'est ouvert à tous !

Le 7 décembre 2017 de 13:45 à 14:30

Cette semaine :

Y.PERIGNON (EMO) will present "Sea states models : Assessing accuracy of the spectral content" at 1:45 PM.

 "Despite the sensitivity of the response of many marine structures to the frequency content of the forcing conditions, the capabilities of spectral estimations has hardly been investigated for hindcast wave models providing either fully resolved spectra, or, as is more generally the case to this date, parameterized spectra evaluated from integral parameters.

This work takes advantage of the HOMERE high-resolution public wave hindcast data set [Boudiere et al. (2013)] as well as the Candhis buoy network for long-term analysis. It extends the diagnosis on spectral accuracy between measurements and hindcast data presented for three measurement locations related to the SEMREV test site in Perignon (2017) to a larger set of measurement stations off the French Atlantic and Channel seaboard. The set of frequency spectra available over the whole Channel and Bay of Biscay area provide a proper basis for a detailed study and comparison of time series. Spectral quantities such as the variance spectral density or wave power are compared with chosen concomitant and collocated in-situ measurement data sets from the Candhis network.

The established spectral diagnosis confirms and emphasizes the strong site dependency in the accuracy of the sea-states assessment, as well as a regional pattern in the signature of the spectral accuracy of wave energy assessment. Contrarily to first hypothesis, no depth dependency can be accounted as a leading factor of spectral inaccuracies. The robustness of the estimation is here confirmed by the low inter-annual variability of the signature when consecutively evaluated on multi year time series. The inaccuracies are shown to be greatly enhanced by extreme sea states in terms of integral wave steepness at some but not all stations. The overall influence of the hindcast accuracy is finally evaluated on the spectral energy yield, which clearly enlightens the epistemic uncertainty associated to a wave energy assessment based only on synthetic data yet fully resolved in frequency"
Publié le 5 décembre 2017 Mis à jour le 5 décembre 2017