Evaluation of a Euler/Lagrange coupling method for the ditching simulation of helicopter structures

This paper deals with the evaluation of a Euler/Lagrange coupling interface implemented in the RADIOSS code, to cope with the modelling of fluid/structure interaction. In the first step, a parametric study on the structure/fluid mesh sizes ratio and the contact gap is performed, through the simulation of a rigid flat plate impact on water. In the second step, the method is evaluated by simulating water impact tests performed at CEAT (French aeronautical test centre) on rigid flat and triangular shapes. The numerical results are compared to the experimental data and allow one to conclude that such a Euler/Lagrange coupling interface constitutes a convenient Solution for modelling fluid/structure interaction, in terms of physical phenomenon modelling, as well as simulation of high penetration inside water. In the final step, works are applied to the simulation of the ditching of a full-scale helicopter structure and confirm the relevance of the method for such a problem. The results are additionally compared with those generated within the research GARTEUR group AG15, which addresses the same topic with the SPH (Smooth Particle Hydrodynamics) method.