Effect of baffles on orbital accelerations — Induced bubble oscillations in microgravity

• Published in: International journal of mechanical sciences Vol. 39; no. 3; pp. 269,273 - 271,288
• Main Authors: Hung, R.J., Pan, H.L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1997; Elsevier
• Subjects: Acceleration; bubble dynamics; Bubbles (in fluids); Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Hydrodynamic waves; Interfaces (materials); Liquids; microgravity orbital accelerations; Oscillations; Physics; slosh dynamics; Spacecraft equipment; Surface tension; Surface waves; Vapors; slosh dynamics; microgravity orbital accelerations; bubble dynamics; Fluid wall interaction; Rotating system; Bubbles; Three dimensional model; Baffles; Liquid vapor interface; Jitter; Oscillations; Cryogenic fluids; Dewars; Microgravity; Liquid sloshing
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/S0020-7403(96)00023-9

The behavior of sloshing dynamics modulated fluid systems driven by the orbital accelerations including gravity gradient and jitter accelerations with partially-filled rotating fluids has been studied. Present study is applicable to a full-scale Gravity Probe-B Spacecraft dewar tank with and without baffle. Results of slosh wave excitation along the liquid—vapor interface induced by jitter acceleration-dominated orbital accelerations provide a torsional moment with an up-and-down movement of bubble oscillations in the rotating dewar. The results show rightward and leftward movement of bubble oscillations transverse to the rotating axis, and up-and-down movement of bubble oscillations longitudinal to the rotating axis of dewar container. The orbital accelerations also induce an eccentric contour of bubble oscillations in a horizontal r—θ plane. As viscous force between liquid—solid interface, and surface tension force between liquid—vapor—solid interface can greatly contribute to the damping effect of slosh wave excitation, the rotating dewar with baffle provides more areas of liquid—solid and liquid—vapor—solid interfaces than that of a rotating dewar without baffle. Results show that the damping effect provide by a baffle reduce the amplitude of slosh wave excitation and reduce the degree of asymmetry in liquid—vapor distribution. Computation of bubble (helium vapor) mass center fluctuations also verifies that a rotating dewar with baffle produces less fluctuations than that of a rotating dewar without baffle.