The XYZ Free Surface Program and Its Application to Transom-Stern Ships with Bow Domes,

Abstract : The XYZ Free Surface Program (XYZFS) is a versatile ship design tool which can be used to predict wave resistance characteristics of a wide variety of hull forms. XYZFS can analyze surface ships with cruiser or transom sterns as well as submerged vehicles. The program uses a Rankine source panel method to compute three-dimensional, steady potential flow about ship hulls. XYZFS calculates the local flow field, wave resistance and wave patterns for ships moving at a constant speed corresponding to a Froude number of 0.2 to 0.6. An estimate of residual resistance can also be obtained. The program is designed to allow calculations both for ships which are held fixed and for ships which are allowed to sink and trim in response to hydrodynamic forces. XYZFS was originally developed by the late Charles W. Dawson at DTNSRDC. He successfully applied the original version of the program to a number of ship hulls including all five of the test cases for the 1979 Workshop on Ship Wave Resistance Computations: the high-speed Athena transom-stern hull, the Wigley parabolic hull, the Inuid hull, the Series 609 cruiser-stern hull, and the low-speed HSVA tanker. The present authors have further developed XYZFS. Results for the two selected hull forms show that XYZFS can now be used for realistic ship models including transom-stern hulls with bow domes. The excellent wave resistance predictions can be largely attributed to recent improvements in the program's computational techniques.