PITCHING MOTIONS OF A MOORED SUBMERGED MINE IN WAVES
DAVID TAYLOR MODEL BASIN WASHINGTON DC HYDROMECHANICS LAB
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This report describes a theoretical and experimental investigation of the pitching motions of a moored, submerged mine. The theoretical predictions are based upon linearized-wave theory as well as the assumptions that the body is slender and axisymmetric and is ballasted to be at equilibrium in the horizontal plane. The mooring cable is assumed to be massless and inelastic the fluid is assumed to be inviscid. The theory results in an equation of undamped motion. Parallel experimental results were obtained on a 2-foot long model in wavelengths ranging from 15 to 55 feet, and these results confirm the theoretical predictions except in the vicinity of resonance, where viscous damping is important. Full-scale predictions are made for the root-mean-square pitching motions in Sea States 4 through 7 for two proposed mine configurations at various depths of submergence. The predicted values are from 1 to 9 degrees in Sea State 4, depending on depth and mine configuration, increasing to greater than 25 degrees in Sea State 7.
- Underwater Ordnance
- Fluid Mechanics