Journal article
Statistical Assessment and Validation of Experimental and Computational Ship Response in Irregular Waves
Journal of verification, validation, and uncertainty quantification, Vol.3(2), 021004
06/01/2018
DOI: 10.1115/1.4041372
Abstract
The objective of this work is to provide and use both experimental fluid dynamics (EFD) data and computational fluid dynamics (CFD) results to validate a regular-wave uncertainty quantification (UQ) model of ship response in irregular waves, based on a set of stochastic regular waves with variable frequency. As a secondary objective, preliminary statistical studies are required to assess EFD and CFD irregular wave errors and uncertainties versus theoretical values and evaluate EFD and CFD resistance and motions uncertainties and, in the latter case, errors versus EFD values. UQ methods include analysis of the autocovariance matrix and block-bootstrap of time series values (primary variable). Additionally, the height (secondary variable) associated with the mean-crossing period is assessed by the bootstrap method. Errors and confidence intervals of statistical estimators are used to define validation criteria. The application is a two-degrees-of-freedom (heave and pitch) towed Delft catamaran with a length between perpendiculars equal to 3 m (scale factor equal to 33), sailing at Froude number equal to 0.425 in head waves at scaled sea state 5. Validation variables are x-force, heave and pitch motions, vertical acceleration of bridge, and vertical velocity of flight deck. Autocovariance and block-bootstrap methods for primary variables provide consistent and complementary results; the autocovariance is used to assess the uncertainty associated with expected values and standard deviations and is able to identify undesired self-repetition in the irregular wave signal; block-bootstrap methods are used to assess additional statistical estimators such as mode and quantiles. Secondary variables are used for an additional assessment of the quality of experimental and simulation data as they are generally more difficult to model and predict than primary variables. Finally, the regular wave UQ model provides a good approximation of the desired irregular wave statistics, with average errors smaller than 5% and validation uncertainties close to 10%.
Details
- Title: Subtitle
- Statistical Assessment and Validation of Experimental and Computational Ship Response in Irregular Waves
- Creators
- Matteo Diez - National Research CouncilRiccardo Broglia - National Research CouncilDanilo Durante - National Research CouncilAngelo Olivieri - National Research CouncilEmilio F Campana - CNR-DIITET, National Reserach Council-Dept. of Engineering, ICT and Technologies for Energy and Transportation, Piazzale Aldo Moro 7, 00185 Roma, ItaliaFrederick Stern - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of verification, validation, and uncertainty quantification, Vol.3(2), 021004
- Publisher
- ASME
- DOI
- 10.1115/1.4041372
- ISSN
- 2377-2158
- eISSN
- 2377-2166
- Grant note
- DOI: 10.13039/100000006, name: Office of Naval Research, award: N00014-14-1-0195, N62909-15-1-2016
- Language
- English
- Date published
- 06/01/2018
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9984196635402771
Metrics
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