Experimental evaluation of structural hull damping coefficient of a hydro-elastic segmented submarine model

This paper presents an experimental study of determining structural damping ratio of the hydro-elastic submarine model. The model test of a hydro-elastic submarine model was conducted at the Towing Tank facility of the Indonesian Hydrodynamic Laboratory (BTH-BPPT). To investigate the effect of the wet and dry damping ratio the vibration tests were performed in both air and water. The experiments in wet and dry condition were undertaken to investigate the influences of the damping ratio at zero forward speed. Vibration tests were also conducted in the Towing Tank at speed in calm water to explore the effect of the forward speed on both fixed and free pitch conditions on the damping ratio. From these experiments it has been found the damping ratios of wet condition are greater than the dry one. The damping ratios increased also as the submarine model speeds forward, whereas both the fixed and free pitch showed an increase in the damping ratio with increase forward speed.