Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible
The paper presents calibration of a time domain numerical model for the motions of the Exwave Semi in high seastates with current. The time domain equations of motion combine linear radiation, linear diffraction and second order wave drift forces, based on MULDIF diffraction code, with nonlinear for...
Published in: | Volume 1: Offshore Technology |
---|---|
Main Authors: | , |
Format: | Book Part |
Language: | English |
Published: |
ASME
2018
|
Subjects: | |
Online Access: | http://hdl.handle.net/11250/2591688 https://doi.org/10.1115/OMAE2018-78753 |
id |
ftsintef:oai:sintef.brage.unit.no:11250/2591688 |
---|---|
record_format |
openpolar |
spelling |
ftsintef:oai:sintef.brage.unit.no:11250/2591688 2023-05-15T14:22:33+02:00 Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible Fonseca, Nuno Stansberg, Carl Trygve 2018-06-25 application/pdf http://hdl.handle.net/11250/2591688 https://doi.org/10.1115/OMAE2018-78753 eng eng ASME ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Volume 1: Offshore Technology - ASME digital collection;OMAE2018-78753 ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Volume 1: Offshore Technology urn:isbn:978-0-7918-5120-3 http://hdl.handle.net/11250/2591688 https://doi.org/10.1115/OMAE2018-78753 cristin:1615101 Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal http://creativecommons.org/licenses/by-nc-nd/4.0/deed.no CC-BY-NC-ND Semi-submersible offshore structures Calibration Mooring Chapter 2018 ftsintef https://doi.org/10.1115/OMAE2018-78753 2021-08-04T11:59:55Z The paper presents calibration of a time domain numerical model for the motions of the Exwave Semi in high seastates with current. The time domain equations of motion combine linear radiation, linear diffraction and second order wave drift forces, based on MULDIF diffraction code, with nonlinear forces from quadratic damping and from the mooring system. Calibration is performed by comparing simulations with model test data and adjusting hydrodynamic coefficients known to be affected by uncertainty. These include wave drift force coefficients, damping and added mass coefficients. Correction of the drift coefficients is based on empirical quadratic transfer functions (QTFs) identified from the test data by a nonlinear data analysis technique known as “cross-bi-spectral analysis”. Initial “uncalibrated” numerical models are based on input from the mooring, vessel mass, MULDIF hydrodynamic analysis, decay tests and current coefficients. They need adjustments for surge and sway. Empirical drift coefficients, natural periods and damping coefficients are then adjusted by matching low frequency surge and sway spectra. Wave-frequency coefficients need no adjustment. Low frequency wave drift forces, damping and added mass need increase in high sea states, in particular with current. Final motion simulations show 30%–40% underestimation in initial simulations, while final calibrated simulations are close to the measured records. Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible acceptedVersion Book Part Arctic SINTEF Open (Brage) Volume 1: Offshore Technology |
institution |
Open Polar |
collection |
SINTEF Open (Brage) |
op_collection_id |
ftsintef |
language |
English |
topic |
Semi-submersible offshore structures Calibration Mooring |
spellingShingle |
Semi-submersible offshore structures Calibration Mooring Fonseca, Nuno Stansberg, Carl Trygve Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
topic_facet |
Semi-submersible offshore structures Calibration Mooring |
description |
The paper presents calibration of a time domain numerical model for the motions of the Exwave Semi in high seastates with current. The time domain equations of motion combine linear radiation, linear diffraction and second order wave drift forces, based on MULDIF diffraction code, with nonlinear forces from quadratic damping and from the mooring system. Calibration is performed by comparing simulations with model test data and adjusting hydrodynamic coefficients known to be affected by uncertainty. These include wave drift force coefficients, damping and added mass coefficients. Correction of the drift coefficients is based on empirical quadratic transfer functions (QTFs) identified from the test data by a nonlinear data analysis technique known as “cross-bi-spectral analysis”. Initial “uncalibrated” numerical models are based on input from the mooring, vessel mass, MULDIF hydrodynamic analysis, decay tests and current coefficients. They need adjustments for surge and sway. Empirical drift coefficients, natural periods and damping coefficients are then adjusted by matching low frequency surge and sway spectra. Wave-frequency coefficients need no adjustment. Low frequency wave drift forces, damping and added mass need increase in high sea states, in particular with current. Final motion simulations show 30%–40% underestimation in initial simulations, while final calibrated simulations are close to the measured records. Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible acceptedVersion |
format |
Book Part |
author |
Fonseca, Nuno Stansberg, Carl Trygve |
author_facet |
Fonseca, Nuno Stansberg, Carl Trygve |
author_sort |
Fonseca, Nuno |
title |
Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
title_short |
Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
title_full |
Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
title_fullStr |
Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
title_full_unstemmed |
Calibration of a Time-Domain Numerical Hydrodynamic Model for Mooring Analysis of a Semi-Submersible |
title_sort |
calibration of a time-domain numerical hydrodynamic model for mooring analysis of a semi-submersible |
publisher |
ASME |
publishDate |
2018 |
url |
http://hdl.handle.net/11250/2591688 https://doi.org/10.1115/OMAE2018-78753 |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Volume 1: Offshore Technology - ASME digital collection;OMAE2018-78753 ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Volume 1: Offshore Technology urn:isbn:978-0-7918-5120-3 http://hdl.handle.net/11250/2591688 https://doi.org/10.1115/OMAE2018-78753 cristin:1615101 |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal http://creativecommons.org/licenses/by-nc-nd/4.0/deed.no |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1115/OMAE2018-78753 |
container_title |
Volume 1: Offshore Technology |
_version_ |
1766295115725275136 |