Estimation of roll damping coefficients based on model tests responses of a FPSO in waves

Claudio A. Rodríguez, Paulo T.T. Esperança, Mauro C. Oliveira

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

1 Citation (Scopus)

Abstract

Roll damping estimation is of great concern for the prediction of motions in waves of ship and offshore platforms, especially when viscous effects are relevant. Although this problem dates back to the times of William Froude, it has regained much attention in the context of the development of the second-generation intact stability criteria of ships, especially because there are still not accurate and efficient tools for roll damping prediction. For offshore applications, a common approach for roll damping estimation is to perform roll decay tests with scale models in calm water and then use the resultant values in the roll equation to predict motions in waves. However, for some wave conditions, the damping coefficients obtained from those tests may not be representative of the actual damping in waves. To assess the influence of wave conditions in the roll damping coefficients, the present work proposes a simplified hybrid approach that combines experimental results from model tests with numerical predictions of roll motion in waves. The numerical tool adopted here is based on a frequency domain single-degree-of-freedom model with linearized external damping that includes viscous effects. A series of experimental model tests with a typical FPSO hull in regular and irregular has been analyzed to obtain the roll damping coefficients in waves. These results are compared with those from decay tests in calm-water as well as from semi-empirical predictions based on Ikeda's method. Despite the linearized assumption, it is expected that the damping coefficients from wave tests provide a more realistic representation of the roll dynamics than those from typical decay tests.

Original languageEnglish
Title of host publicationASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering
Subtitle of host publicationVolume 7B: Ocean Engineering
Place of PublicationNew York, NY
PublisherAmerican Society of Mechanical Engineers(ASME)
Number of pages10
ISBN (Electronic)9780791858851
DOIs
Publication statusPublished - 11 Nov 2019
EventASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019 - Glasgow, United Kingdom
Duration: 9 Jun 201914 Jun 2019

Conference

ConferenceASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019
Country/TerritoryUnited Kingdom
CityGlasgow
Period9/06/1914/06/19

Keywords

  • decay tests
  • irregular waves
  • RAO
  • seakeeping
  • viscous damping

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