This paper proposes an analytic method to solve the wave diffraction problem on the vertical cylinder with the cross-section of arbitrary shape by using conformal transformation. The derivation solution was formulated in this paper, and results were compared with those of numerical methods. The excellent agreement shows that the analytic solution is correct and applies to non-circular cross-section vertical cylinders. The proposed method provides a uniform view for the noncircular cross-section vertical cylinder in the water. The model of wave scattering by a non-circular cross-section is a general fundamental mathematical problem, not only in hydrodynamics but also in other disciplines such as acoustics, electromagnetics. The techniques to handle the governing equation and boundary conditions with the help of conformal transformation in this paper can provide a reference for other similar mathematical physics problems.
Wave loads calculation is the essential work in offshore platform design, and only a few geometry shapes can be solved analytically, such as vertical or horizontal round cylinders. With the help of conformal mapping technology, the ship's cross-section can be mapped to halfcircle to get wave loads.