Numerical Approach of Nonlinear Free Surface Flow around Nonlifting or Lifting Body Using Panel Method

Abstract

To predict hydrodynamic characteristics of high-speed crafts, a lifting-body theory is needed, because lifting bodies such as hydrofoils, fins and so on, are generally attached to recent high-speed crafts to improve the hydrodynamic performance like wave-making resistance, lift and so on. For this purpose, PAFS (Panel method Applied to Free Surface flow) based on the potential theory is suggested by the authors, in which Morino's panel method is extended to the problem of free surface flow based on Kelvin's linearized free surface condition. In order to get more accurate results based on PAFS, however, it is expected that the nonlinear effects of free surface conditions should be taken into consideration for the free surface flows around nonlifting/lifting bodies. In the present study, the second-order effect of nonlinear free surface conditions is formulated by using perturbation technique. Numerical examples are shown for a few nonlifting/lifting models to evaluate the effectiveness of PAFS with second-order effect of nonlinear free surface conditions.