Superfluid helium sloshing dynamics induced oscillations and fluctuations of angular momentum, force and moment actuated on spacecraft driven by gravity gradient or jitter acceleration associated with slew motion
Abstract
The generalized mathematical formulation of sloshing dynamics for partially filled liquid of cryogenic superfluid helium II in dewar containers driven by the gravity gradient and jitter accelerations associated with slew motion for the purpose to perform scientific observation during the normal spacecraft operation are investigated. An example is given with the Advanced XRay Astrophysics FacilitySpectroscopy (AXAFS) for slew motion which is responsible for the sloshing dynamics. The jitter accelerations include slew motion, spinning motion, atmospheric drag on the spacecraft, spacecraft attitude motions arising from machinery vibrations, thruster firing, pointing control of spacecraft, crew motion, etc. Explicit mathematical expressions to cover these forces acting on the spacecraft fluid systems are derived. The numerical computation of sloshing dynamics is based on the noninertia frame spacecraft bound coordinate, and solve timedependent, threedimensional formulations of partial differential equations subject to initial and boundary conditions. The explicit mathematical expressions of boundary conditions to cover capillary force effect on the liquidvapor interface in microgravity environments are also derived. The formulations of fluid moment and angular moment fluctuations in fluid profiles induced by the sloshing dynamics, together with fluid stress and moment fluctuations exerted on the spacecraft dewar containers have also been derived. Examples are also given for cases applicable to the AXAFS spacecraft sloshing dynamics associated with slew motion.
 Publication:

Alabama Univ., Huntsville Report
 Pub Date:
 February 1994
 Bibcode:
 1994alab.reptR....H
 Keywords:

 Dynamic Models;
 Liquid Helium 2;
 Liquid Sloshing;
 Spacecraft Control;
 Spacecraft Motion;
 Spacecraft Stability;
 Superfluidity;
 Aerodynamic Drag;
 Angular Momentum;
 Attitude (Inclination);
 LiquidVapor Interfaces;
 Mathematical Models;
 Spacecraft Environments;
 Vibration;
 Fluid Mechanics and Heat Transfer