Joint High Speed Sealift (JHSS) Segmented Model Test Data Analysis and Validation of Numerical Simulations

The Joint High Speed Sealift (JHSS) segmented model (Model 5663) tests performed in 2007 at Naval Surface Warfare Center, Carderock Division (NSWCCD) were designed to provide a large data set for validation of numerical simulations. The segmented model had a scaled longitudinal stiffness in bending and torsion provided by an aluminum backspline. The hull of the model was cut into segments to lessen the stiffness effects of the shell. The model was self-propelled and steered during data collection. Preliminary validation work performed soon after the experiments with LAMP (Large Amplitude Motions Program) and Numerical Flow Analysis (NFA) showed favorable results. Additionally, the segmented model provided structural loading results that were used to understand hydroelastic phenomena such as springing and whipping. A study of the irregular seas cases showed that springing does not have a large effect on the JHSS model. The whipping response was explored for regular seas runs, with some cases showing significant loads on the ship. Efforts to understand and predict the whipping response fared poorly, indicating that this complex phenomenon requires additional study and more complex simulation tools.