Simulation of sloshing dynamics induced forces and torques actuated on Dewar container driven by gravity gradient and jitter accelerations in microgravity

Abstract

The dynamical behavior of spacecraft propellant affected by the asymmetric combined gravity gradient and jitter accelerations, in particular the effect of surface tension on partially-filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank have been simulated and investigated. Three cases are studied: gravity gradient-dominated acceleration, equally-weighted gravity gradient and jitter accelerations, and gravity jitter-dominated acceleration. Results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient-dominated acceleration indicate that the gravity gradient-dominated acceleration is equivalent to the combined effect of a twisting force and torsional moment acting on the spacecraft. The results are clearly seen from left-side up and right-side down oscillations of the bubble in the horizontal cross-section of profiles of rotating dewar for the oscillations driven by gravity gradient-dominated acceleration. Results of slosh wave excitation along the liquid-vapor interface induced by gravity jitter-dominated acceleration indicated equivalence to time-dependent oscillatory forces which push a bubble in the combined bubble motion of down-and-up and leftward-and-rightward as the bubble is rotating with respect to the rotating dewar axis. Fluctuations of fluid forces, torque and moment arm exerted on the dewar wall of the container caused by slosh wave excitations driven by the combined gravity gradient and gravity jitter accelerations are also simulated and investigated.