Green Water and Wave impacts are amongst the most severe and dangerous loads that effect offshore structures. Even if many design procedures are well established, they can over or underestimate the structural loading in complex conditions as they are outside of their application scope. This therefore leads to over designed and expensive structures, or to under designed structures leading to dangerous situations. The calculation of complex structure loadings is therefore a key issue for engineering companies.
HydrOcean in the previous SNAME symposium presented a methodology to evaluate green water phenomena developed in cooperation with the French offshore industry, namely Total S.A. and Technip. This methodology is based on the use of complementary tools from potential linear flow solvers in order to perform the screening up to the very precise CFD simulations to simulate the wave impact over the platform topside structure.
More precisely on this latter aspect, HydrOcean in cooperation with NextFlow software is continuously improving its CFD numerical tools. Recently, in the SPH-flow software the adaptive particle refinement technique has been implemented which allows to improve substantially the quality of the results at the same time reducing the associated CPU costs.
In the previous article it was shown that, it was necessary to increase the number of particles to 24 million in order to start detecting with a reasonable precision the impact pressure (in comparison to experiments). Here, it will be shown that this number of particle can be decreased and the quality of the pressure signal obtained numerically is increased.
This technique is then validated and put to proof by performing the same test case as in the previous article. Then, an industrial case of a FLNG in a harsh irregular sea-state is shown. The images below illustrate the simulations and comparisons to experiments with this new technique.