Accession Number:

ADA162686

Title:

Viscous Fluid Motion in a Spinning and Nutating Cylinder

Descriptive Note:

Contractor rept. Aug 1983-Apr 1985

Corporate Author:

VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS

Report Date:

1985-11-01

Pagination or Media Count:

119.0

Abstract:

Spin-stabilized projectiles with liquid payloads can experience a severe flight instability characterized by a rapid yaw-angle growth and a simultaneous loss in spin rate. Laboratory experiments and field tests have shown that this instability originates from the internal fluid motion in the range of high viscosity. After evaluation of the experimental data and analysis of the equations for the fluid motion in a spinning and nutating cylinder, we have developed a simple model of this flow. Disregarding the finite length of the cylinder, this model provides the flow field and the viscous contribution to the liquid moments in analytical form. At low Reynolds number, the flow field agrees well with computational results for the center section of a cylinder of aspect ratio 4.3. The roll moment caused by this flow largely agrees with experimental data for a wide range of reynolds numbers. Estimates of the temperature variation indicate that discrepancies at very low Reynolds numbers may originate from associated changes of the viscosity during the experiments. The flow in an infinitely long cylinder has been utilized as a basic flow subject to axially periodic cellular disturbances. Both, the inviscid and the viscous situations have been studied. Parametric excitation of the cellular motions has been found at low Reynolds numbers. A small experiment has been designed to visualize this cellular motion in a finite-length cylinder.

Subject Categories:

  • Ammunition and Explosives
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE