THREE-DIMENSIONAL SOLUTIONS FOR THE RADIATION PROBLEMS OF AN OSCILLATING SHIP WITH SPEED

Article type: Research Article

Authors: Fang, Ming-Chung | Lin, Han-Ping

Affiliations: National Cheng Kung University, Department of Naval Architecture and Marine Engineering, Tainan, Taiwan

Abstract: In the paper, the radiation problems of a moving ship are solved by using the 3D source distribution technique incorporated in a panel method. The added mass and damping coefficient with speed effects are obtained through the modifications of the pressure calculation, body boundary condition and additional contour integral along the interaction of hull surface and the free surface. In order to eliminate the mathematical difficulties associated with the numerical evaluation of the exact Green function, a simplified free surface condition is assumed. The series expansions of the Telste & Noblesse algorithm and the complex plane contour integral of the Shen & Farell algorithm are used for solving the corresponding Green functions and their derivatives. Three different numerical formulas are derived to calculate the added mass and damping coefficient and are discussed in the paper. The three-dimensional method developed in the paper can offer an efficient analytical tool for estimating the corresponding hydrodynamic coefficients of an oscillating ship with speed in calm water. The effect of steady flow is generally small in the present radiation problems and may be negligible. However, the effect of the water line integral is significant for pitch and yaw modes and may not be neglected. It is also found that using the techniques incorporated with a suitable body mesh distribution can lead to satisfactory results.

Journal: International Shipbuilding Progress, vol. 47, no. 449, pp. 95-124, 2000