Maneuvering characteristics in calm water and regular waves for ONR Tumblehome

Standard maneuvering tests were executed at the IIHR wave basin using free-running model. Experiments in calm water as well as wave were performed for a surface combatant with primary focus on establishing a validation benchmark dataset for an unsteady Reynolds-averaged Navier-Stokes (RANS)-based computational fluid dynamics (CFD) code used for computing both air and water flow around a ship. Experimental data from this study will also be used in developing a mathematical model for computing the external forces exerted on the ship model during maneuvering. The geometry is 1/49 scale fully appended ONR Tumblehome model 5613, with a length of 3.147 m. Tests are performed in 20 x 40 x 4.5 m wave basin which is equipped with six plunger-type wave makers, free-running system, as well as carriage tracking system. The maneuvering tests included course keeping, zigzag, and turning tests in head and following waves as well as calm water. Course keeping and zigzag tests were performed at Froude number 0.2 while turning tests were performed at Froude numbers 0.1, 0.2, and 0.3. While the wave height to wavelength ratio was held constant at 0.02 for all the test cases, experiments were performed at three different wavelengths for each Froude number case at different wave encounter angles. Maneuvering trajectories for each test as well as results such as roll, pitch, yaw and yaw rate results were analyzed for all tests. Drift angle, drifting distance, tactical diameter, advance and transfer results from turning tests were obtained and tactical diameter and advance are compared to other facilities data. 1st and 2nd overshoot angles results from zigzag tests and counter rudder angle and speed loss in course keeping were obtained and documented along with the turning test results to help in developing a mathematical model for calculating the forces and moments acting on the ship model and to establish a benchmark data for the CFD validation use.