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Study on the truncation factor of mooring system for a ultra-deep water platform
Citation Link: https://doi.org/10.15480/882.3350
Publikationstyp
Conference Paper
Date Issued
2019-09
Sprache
English
Herausgeber*innen
TORE-DOI
TORE-URI
Article Number
55
Citation
11th International Workshop on Ship and Marine Hydrodynamics (IWSH2019), Paper 55
Contribution to Conference
With the continually increasing water depth of offshore structures being moored, it become harder to study the behaviour of such deep water mooring systems adopting model test with conventional scale ratio due to the limited depth and width of available model basins. According to this condition, an alternative approach is equivalent truncation method, which has been proved to be a feasible method. However, the effect of truncation factor is still not clear, when the truncation factor is too small, it is difficult to get a satisfied mooring system owing to the effect of the line dynamics and other factors.
This paper presents one taut mooring system of semi-submersible in full water depth of 1200m. Model test research using scale ratio of 1:62.5 is carried out in Deep Water Ocean Basin of CSSRC, which can satisfy the full depth model test demand which need the water depth 19.2m in model scale. And the mooring systems in water depth of 750m and 250m are initially truncated designed based on the static equivalent characteristics similar criteria, then optimize the truncation mooring system through iteration process via static load optimization and dynamic optimization. Truncation model test are numerical reconstructed, then extrapolated to full depth, which are compared with the full depth results subsequently. The comparison results show that the extrapolated results based on 750m water depth are coincident well with the full depth results, but the extrapolated results based on 250m do not dovetail with the full depth results. According to the comparison results, the effect of truncation factor to predict full depth results is analysed, pilot study show that aiming at this mooring system scheme, when the truncation factor is more than about 0.45, the predicted results based on truncation model test can be reliable.
This paper presents one taut mooring system of semi-submersible in full water depth of 1200m. Model test research using scale ratio of 1:62.5 is carried out in Deep Water Ocean Basin of CSSRC, which can satisfy the full depth model test demand which need the water depth 19.2m in model scale. And the mooring systems in water depth of 750m and 250m are initially truncated designed based on the static equivalent characteristics similar criteria, then optimize the truncation mooring system through iteration process via static load optimization and dynamic optimization. Truncation model test are numerical reconstructed, then extrapolated to full depth, which are compared with the full depth results subsequently. The comparison results show that the extrapolated results based on 750m water depth are coincident well with the full depth results, but the extrapolated results based on 250m do not dovetail with the full depth results. According to the comparison results, the effect of truncation factor to predict full depth results is analysed, pilot study show that aiming at this mooring system scheme, when the truncation factor is more than about 0.45, the predicted results based on truncation model test can be reliable.
Subjects
Truncation factor
DDC Class
600: Technik
620: Ingenieurwissenschaften
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