WAVE-INDUCED MOTIONS OF A ROCKET VEHICLE DRIFTING IN A VERTICAL ATTITUDE
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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Measurements were made of the movements in heave and pitch of a 1-to-120 scale model of a million lb solid-propellant rocket vehicle 175 ft long and about 12-12 feet in diameter. Heave measurements agreed well with those calculated. No pitch calculations were made. Heave and pitch were linear functions of wave height and nonlinear functions of wave period. In deep water, the ratio of heave to wave height was 0.1 for waves with a 6-sec period and 0.4 for waves with a 12sec period. The maximum deviation from the vertical was 9 min of arc for waves 1 ft in height with a 6-sec period and 11 min for waves 1 ft in height with a 12-sec period. The frequency of occurrence of certain levels in pitch and heave in ocean-wave environments were calculated. A vehicle drifting in a fully arisen sea at wind speed of 10 and 20 knots had a significant heave of respectively 0.4 and 1.3 ft and a significant pitch of respectively 32 and 77 min of arc. The movements of the vehicle in pitch and heave could be decreased by lowering its flotation chamber and by attaching fins or plates and a weight near its tail end.
- Fluid Mechanics