عباس دشتی منش

The present study attempts to mathematically model forced roll mechanism developed by Judge (2010) in order to determine hydrodynamic roll coefficients. To achieve this goal, 2.5D theory is used by which forces and moments acting on the bottom of hull are determined. The pressure acting on each section, is computed using potential theory, and considering impact velocity as well as roll velocity. The roll moment acting on each section is computed using pressure and the roll moment acting on the craft is determined using integration of the sectional moment. In addition, contribution of hydrostatic force in restoring moment is taken into account. The hydrodynamic and hydrostatic forces are reduced using a transom reduction formula. It is attempted, to assess, validity of the present method, by comparing predicted coefficient against previous experimental data.