Moment exerted on a coning projectile by a spinning liquid in a cylindrical cavity containing a porous medium
Abstract
White Phosphorous (WP) impregnated felt wedges are used as a payload in the M825 improved smoke projectile. An assumption made in this work in that the WP is in a liquid state (i.e., temperature greater than 44 degrees C) where such payloads have been seen to cause flight instabilities. The analytical results given here formulate an initial effort to gain an understanding of the dynamics of a projectile interacting with a WP/felt payload. The analytical methods used here are a simple extension of previous methods used to describe bulkfilled liquid payloads. Moments are predicted due to an inviscid liquid moving through a ridged porous medium which is confined to a spinning cylindrical cavity undergoing coning motion. A drag term is added to the classical Stewartson theory which is used to describe the flow in the porous media. The cylindrical cavity is assumed to consist of several chambers of circular cross section and uniform height, each separated by solid endcaps. This porous media theory is used to calculate the total liquid side moments exerted by all the chambers in the cylinder. Results are presented for a range of coning frequencies, fineness ratios, and porous drag coefficients.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 June 1988
 Bibcode:
 1988STIN...8910239C
 Keywords:

 Liquid Filled Shells;
 Moment Distribution;
 Moments;
 Projectiles;
 Rotating Liquids;
 Spin Dynamics;
 Circular Cylinders;
 Conical Bodies;
 Drag;
 Felts;
 Impact;
 Inviscid Flow;
 Payloads;
 Phosphorus;
 Porous Materials;
 Spin Stabilization;
 Fluid Mechanics and Heat Transfer