The effect of hull emergence angle on the near field formulation of added resistance

The added resistance of a ship is an important hydrodynamic parameter which affects the performance of a vessel traveling through ocean waves. A numerical method for estimating the added resistance is developed based on the near field pressure integration method which is then improved to include the effect of the hull flare angle at the mean water surface. The three dimensional free surface Green function source distribution method is used to solve the radiation-diffraction problem within the potential flow assumptions. The developed theory is then applied to develop a new efficient computer program. The validity of the developed code is established through comparison with available numerical and experimental results for a range of structures. This includes comparison with Rankine source based near field and far field methods and recent experimental results. The key finding of the present research is the effect of the hull emergence angle on added resistance which is often ignored in many present numerical methods. Significant differences in predicted added resistance and drift forces are found for a Ro-Ro ship with a non-wall sided hull form.