Highly Viscous Fluid Flow in a Spinning and Nutating Cylinder,

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. Evaluation of the experimental data and analysis of the equations for the fluid motion in a spinning and nutating cylinder suggest a theoretical approach in three major steps 1 analysis of the steady viscous flow in an infinitely long cylinder, 2 hydrodynamic stability analysis of this basic flow, and 3 analysis of the end effects. The basic flow has been found in analytical form. At low Reynolds number, this flow agrees well with computational results for the center section of a cylinder of aspect ratio 4.3. The despin moment caused by this flow largely agrees with experimental data for a wide range of Reynolds numbers. Current work aims at the stability of this flow. Author