Marco Bovio, Senior Research Hydromechanics Engineer at Damen, presented details of internal research CFD based project ‘Gone With The Wind’ (GWTW), which studies the capability of CFD to accurately model the aerodynamic forces that act upon vessels.
The purpose of this project is to address the challenge of meeting the requirements of the IMO regulation 749.18 which aims to ensure that vessels have sufficient transversal stability to resist over-rolling in severe side winds.
This makes it difficult for long, slender vessels to satisfy the empirical requirements of the rule without undertaking extensive and costly experimentation, Damen said.
Thus, GWTW wanted to develop a CFD methodology to replace the physical assessments for vessels such as Damen’s FCS range that will demonstrate compliance to the satisfaction of the classification societies.
Damen said that GWTW has two main elements:
- The development of a CFD methodology in partnership with Numeca
- Conduction of physical tests that are needed to validate and verify the CFD calculations, using a 1:18 scale model of Damen’s FCS 3307.
“The model has been evaluated in a wind tunnel using various heading and heeling angles while the computational software has been configured to reproduce the conditions in the wind tunnel to a high degree of accuracy. Simulations using the FCS 3307 were then run using two separate CFD mathematical models; URANS and DES, to determine their efficacy and compare them with the findings of the wind tunnel testing programme,” Damen highlighted.
After the test being conducted, the CFD model has reproduced the wind tunnel experiment and tunnel apparatus to a high degree of accuracy across a range of simulated conditions and achieved good correlation for forces and moments at various heading and heeling angles, according to the company.
The next step is to use this methodology to full-scale prediction.
At the same time, activities are currently taking place to carry out the CFD validation of the hydrodynamic related part of the study, which will complete the demonstration of how vessels of this type achieve the transversal stability required to resist over-rolling in severe side winds, and so satisfy the demands of the regulation.
The final objective of the project is to present the fully virtualised assessment procedure to the Classification Societies in order to have this generally accepted for compliance purposes, Damen noted.
To see more details about the ‘Gone With The Wind’ project, click below