Pressure measurements of a rotating liquid for impulsive coning motion

A spinning cylinder which contained a liquid in rigid body rotation was impulsively forced to cone at a small angle away from a vertical orientation. The response of the fluid to this abrupt, circular coning motion was measured by pressure transducers that were located in the end wall of the cylinder. The time for the fluid to achieve a steady state response to the impulsive coning motion was several seconds. Cone-up times were experimentally determined for a range of coning frequencies. The Reynolds number was 5.23 x 10 to the 5th power. In general, the cone-up times were comparable in magnitude to the spin-up time (the time required by the liquid to adjust to an impulsive change in the spin rate of the cylinder). These experiments indicate that numerical simulations for liquid payloads carried by spin-stabilized, gun launched projectiles must account for both spin-up and cone-up and that these effects must be treated simultaneously.