| This thesis proposes a two-dimensional theory for asymmetric impact of hard chine vessel sections with arbitrary geometry. Interaction between two asymmetric body sides is incorporated into the hydrodynamic impact model. Two types of flow models are established for cases of small and large asymmetry; the distinguishing difference being whether the flow attaches or separates at the keel on the first instances of impact. The method of vortex distributions is applied for modeling these nonlinear boundary value problems. Solutions are carried out through a time-marching procedure with free-vortex shedding (jet-spraying). Initial conditions are derived from basic solutions for straight-side contours, e.g., wedges, with constant impact velocity. The proposed method provides transient sectional slamming loads (including dynamic pressure distributions, lifting forces and restoring moments), as well as jet formation dynamics. Computational results are presented for various sectional contours with constant or variable impact velocity. The model is applicable for asymmetrical planing analysis of slender bodies, and applied in the prediction of the dynamic wetted surface during steady prismatic planing, with zero or non-zero heel angle. The present theory is also used to solve for the dynamic response of a vessel during free-fall impact. For asymmetric cases, the vessel's resultant motions are coupled by the vertical penetration and self-righting rolling. Experimental verifications demonstrate generally good agreement with the present theoretical simulations. |
