A comprehensive experimental investigation of total drag and wave height of ONR Tumblehome, including uncertainty analysis

A comprehensive hydrodynamic investigation of the 48.9 scale ONR Tumblehome (ONRT) form has been made by experiments carried out in Ata Nutku Ship Model Testing Laboratory of Istanbul Technical University (ITU-AN). Starting from the bare hull of ONRT hull, drag tests w/or w/o rudders, shafts and brackets, and the fully appended ONRT hull have sequentially been performed in the range of Froude number, 0.16≤Fr ≤ 0.36. The repeatability of drag tests of fully appended ONRT hull has been presented by uncertainty analysis between 0.10≤ Fr ≤ 0.42. The total drag (R_TM) of ONRT form with the expanded uncertainty was estimated as 4.615 ± 1.098% N at Fr = 0.20, and 11.121 0.636% N at Fr = 0.30. At Fr = 0.20, it was concluded that the total drag (R_TM) of fully appended model was 79.21% bare hull, 7.10% rudders, 8.78% shafts and brackets, and 4.91% bilge keels. The drag tests of fully appended ONRT performed at ITU-AN was also compared with those of carried out at IOWA-IIHR and OU-NAOE. New wave heights at two planes (namely, y/L_WL = 0.1557 and y/L_WL = 0.3623) of ONRT were also measured and presented at five different Fr numbers. These measurements were compared with those of CFD performed before. A very good agreement has been obtained.