Accession Number : ADA195291

Title :   Moment Exerted on a Coning Projectile by a Spinning Liquid in a Cylindrical Cavity Containing a Porous Medium.

Descriptive Note : Memorandum rept.,

Corporate Author : ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s) : Cooper, Gene R

PDF Url : ADA195291

Report Date : Jun 1988

Pagination or Media Count : 35

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 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 bulk-filled 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. Keywords: Cylindrical cavity, Inviscid flow, Porous media, Rotating liquid.

Descriptors :   *SMOKE PROJECTILES, *LIQUID FILLED PROJECTILES, *EXTERIOR BALLISTICS, CAVITIES, CIRCULAR, COEFFICIENTS, CROSS SECTIONS, CYLINDRICAL BODIES, DRAG, DYNAMICS, FILLING, FINES, HEIGHT, INVISCID FLOW, LIQUIDS, MEDIA, MOMENTS, PAYLOAD, POROSITY, POROUS MATERIALS, RATIOS, ROTATION, SIDES, SPINNING(MOTION), THEORY, WHITE PHOSPHORUS, ALIGNMENT

Subject Categories : Ballistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE